Bowel pain: causes, diagnosis, treatment

Bowel pain is not a diagnosis in itself, but a symptom that can arise from both relatively harmless functional disorders and conditions requiring urgent care. In practice, patients often refer to any pain in the lower abdomen, around the navel, or throughout the abdomen as "bowel pain," but the source of the symptom is not always located in the intestines: similar sensations can be caused by the stomach, bile ducts, pancreas, urinary tract, appendix, and pelvic organs. [1]

Intestinal pain can be spasmodic, colicky, aching, dull, distending, or burning. The physician considers not only the pain's severity, but also its duration, suddenness, and association with eating, bowel movements, bloating, fever, blood in the stool, weight loss, and nocturnal symptoms. It is this combination of symptoms that helps differentiate a functional disorder from inflammation, infection, obstruction, or ischemia. [2]

The most common cause of chronic, recurring intestinal pain in adults is irritable bowel syndrome. It is characterized by recurrent abdominal pain associated with defecation, as well as changes in stool frequency, stool form, or both. Current guidelines emphasize that this diagnosis is not made "by exclusion," but rather based on a characteristic clinical picture in the absence of warning signs. [3]

But not every intestinal pain is functional. If the pain is accompanied by blood in the stool, fever, persistent vomiting, weight loss, anemia, nocturnal diarrhea, severe weakness, inability to pass gas, or sudden, severe pain, the likelihood of an organic pathology increases significantly. In such cases, an active search for the cause is required, and sometimes immediate hospitalization.

It's important to understand one more thing: intestinal pain cannot be assessed separately from stool. Diarrhea, constipation, mucus, blood, black, tarry stools, rumbling, bloating, a feeling of incomplete evacuation, tenesmus, painful false urges—all these aren't "extra details" but are actually key to the diagnosis. The more accurately the stool and accompanying symptoms are described, the faster the correct examination can be determined. [5]

Table 1. What the nature of pain most often indicates

The nature of pain	What is more often assumed	What increases alertness
Spastic, wave-like	irritable bowel syndrome, constipation, intestinal colic, partial obstruction	vomiting, lack of gas and stool, increasing bloating
Constant local pain in the lower left abdomen	diverticulitis	fever, tenderness to palpation, worsening over 1-3 days
Pain with diarrhea and fever	infectious colitis	blood or mucus in the stool, dehydration
Pain with blood in stool and weight loss	inflammatory bowel disease, tumor, ischemia	anemia, night symptoms, age and family risk factors
Sudden, very severe pain that is not consistent with examination	intestinal ischemia	vascular risk factors, metabolic acidosis, acute deterioration
Pain with prolonged constipation	chronic constipation, functional disorder, less commonly a tumor	blood in the stool, weight loss, inability to pass gas

The table is based on current recommendations for irritable bowel syndrome, diverticular disease, infectious diarrhea, constipation, intestinal ischemia, and symptoms of colorectal cancer. [6]

The main causes of intestinal pain

Irritable bowel syndrome is the most common cause of chronic or recurrent pain without structural bowel damage. It is characterized by pain or discomfort associated with defecation, as well as changes in stool frequency or form. Some patients experience predominantly diarrhea, others constipation, and still others alternate between the two. Bloating, rumbling, and a feeling of incomplete evacuation are often associated. [7]

Infectious causes often have an acute onset. Infectious colitis and gastroenteritis are characterized by abdominal pain, diarrhea, and sometimes nausea and vomiting, while bacterial infections may cause fever, mucus or blood in the stool, and severe cramping. Guidelines for infectious diarrhea recommend more vigorous evaluation of patients with blood, mucus, high fever, severe abdominal pain, or signs of sepsis. [8]

Inflammatory bowel disease, primarily ulcerative colitis and Crohn's disease, should be suspected when pain is accompanied by chronic diarrhea, blood in the stool, weight loss, fatigue, anemia, and sometimes extraintestinal manifestations. Ulcerative colitis is characterized by bloody stools and tenesmus, and the severity of symptoms can vary from moderate to very severe. Fecal calprotectin is a valuable initial screening test because it increases with inflammation of the intestinal mucosa. [9]

Diverticular disease and diverticulitis are more common in adults and older patients. Acute diverticulitis is most typically characterized by pain in the lower left abdomen, often accompanied by fever, nausea, constipation, or diarrhea. Current guidelines emphasize that not all uncomplicated diverticulitis requires mandatory antibiotics: in immunocompetent patients with mild cases, antibiotics can be used selectively rather than automatically. [10]

Chronic constipation also often causes "intestinal" pain: distension, heaviness, cramping, a feeling of fullness, incomplete evacuation, and bloating. But constipation comes with an important caveat: persistent pain, blood in the stool, vomiting, inability to pass gas, weight loss, and a family history of colon cancer require a more serious cause. In other words, pain associated with constipation isn't always simply a consequence of a "lazy bowel." [11]

Celiac disease, colorectal cancer, intestinal obstruction, and intestinal ischemia should also be considered. Celiac disease can present not only with diarrhea but also with bloating, pain, iron deficiency, and weight loss. Colorectal cancer can cause prolonged pain, changes in stool, blood, and anemia. Obstruction is often accompanied by cramping pain, vomiting, bloating, and a lack of gas, while intestinal ischemia is known to cause severe pain, sometimes disproportionate to the physical findings. [12]

Table 2. Common causes of intestinal pain and their differences

Cause	How it usually manifests itself	What is especially important
Irritable bowel syndrome	recurring pain, association with bowel movements, change in stool pattern or frequency	no systemic inflammation, no alarming signs
Infectious colitis	acute onset, diarrhea, cramps	fever, blood, mucus, dehydration
Ulcerative colitis and Crohn's disease	pain, chronic diarrhea, blood, weight loss	elevated calprotectin, endoscopy required
Diverticulitis	most often local pain on the left side of the lower abdomen	fever and complications are possible
Chronic constipation	distension, pain, rare or hard stools	exclude warning signs and obstruction
Celiac disease	bloating, pain, diarrhea, or hidden malabsorption	serology before starting a gluten-free diet
Obstruction	colic, vomiting, bloating, no gas	emergency condition
Intestinal ischemia	sudden severe pain	urgent assessment required

The table is based on current sources on irritable bowel syndrome, infectious diarrhea, inflammatory bowel disease, diverticulitis, celiac disease, constipation, obstruction, and ischemia. [13]

Red flags and when urgent help is needed

The most important principle for intestinal pain is to first rule out urgency and only then consider a functional disorder. Urgent medical attention is needed in the presence of sudden severe pain, rapidly worsening symptoms, fainting, a drop in blood pressure, severe weakness, abdominal muscle tension, repeated vomiting, inability to drink fluids, complete cessation of gas or stool passage, and the appearance of blood or black, tarry stool. These signs are considered alarming because they can occur with intestinal obstruction, perforation, bleeding, and ischemia.

A particularly alarming scenario is the combination of pain with weight loss, anemia, nocturnal diarrhea, or blood in the stool. This combination increases the likelihood of inflammatory bowel disease or cancer and requires not endless self-medication, but an examination with tests and often a colonoscopy. For colorectal cancer, official sources specifically list a change in bowel habits, blood, persistent abdominal pain, weakness, and unexplained weight loss. [15]

Age also changes the threshold for suspicion. According to cancer detection guidelines, in adults over 40, the combination of unexplained abdominal pain and weight loss already requires an accelerated risk assessment for colorectal cancer, and in cases of rectal bleeding, iron deficiency anemia, and persistent changes in bowel habits, the need for testing is even greater. This doesn't mean that every patient with pain has cancer, but it does mean that such symptoms should not be attributed to "dysbacteriosis" without testing. [16]

Constipation has its own warning signs. If constipation is accompanied by persistent abdominal pain, blood in the stool, vomiting, fever, inability to pass gas, or unintentional weight loss, this is no longer typical functional constipation and not a situation for long-term, random home treatment with laxatives. This combination of symptoms requires ruling out obstruction, tumor, and other organic causes. [17]

There's also a specific "vascular" red flag: very severe pain that seems out of proportion to the physical findings. This is how early mesenteric ischemia is often described, when the patient experiences severe pain, but the abdomen may not yet appear sharply tense in the early stages. This is a rare but dangerous condition, and missing it is one of the most serious diagnostic errors in abdominal pain. [18]

Table 3. Warning signs of intestinal pain

Sign	Why is it dangerous?	What to do
Sudden, very severe pain	ischemia, perforation, acute abdomen are possible	seek emergency care immediately
Pain with no gas or stool	obstruction is possible	urgent in-person assessment
Pain with repeated vomiting and bloating	risk of obstruction and dehydration	see a doctor urgently
Pain with blood in stool or black stool	bleeding, colitis, tumor, ischemia	urgent assessment
Pain with weight loss, anemia, night symptoms	organic pathology, including inflammation and cancer, is possible	accelerated examination
Pain with fever and severe diarrhea	infectious or inflammatory process	tests and in-person assessment

The basis of the table is recommendations for emergency symptoms, obstruction, ischemia, constipation and recognition of colorectal cancer.[19]

Diagnostics

Diagnosis begins not with a colonoscopy, but with a proper clinical interview. The doctor will determine when the pain first appeared, how it manifests itself over time, where exactly it is felt, whether it is related to bowel movements, food, stress, the menstrual cycle, recent travel history, whether antibiotics have been taken, and whether there is a family history of inflammatory bowel disease, celiac disease, or colorectal cancer. At this stage, patients can already be divided into low- and high-risk groups. [20]

If the clinical picture is typical of irritable bowel syndrome and there are no alarming signs, current guidelines allow for a "positive" diagnostic strategy rather than sending the patient immediately through a long series of expensive tests. This is one of the most important advances in modern gastroenterology: functional disorders should be recognized, not diagnosed only after dozens of negative tests. [21]

When there is uncertainty between functional and inflammatory pathology, fecal calprotectin is particularly useful. It is recommended as an adjunctive test in adults with recent lower gastrointestinal symptoms, when it is necessary to differentiate between irritable bowel syndrome and inflammatory bowel disease. A low result makes active inflammation less likely, while an elevated result reinforces the indication for endoscopy. [22]

In acute diarrhea, a stool test is not necessary for everyone. It is recommended for those with a high fever, blood or mucus in the stool, severe cramping, severe abdominal pain, septicemia, immunodeficiency, or epidemiological risk factors. This approach is consistent with recommendations for infectious diarrhea and helps avoid overuse of antibiotics while still detecting a serious bacterial infection. [23]

If celiac disease is suspected, the correct approach is to first conduct a serological evaluation rather than immediately switch to a gluten-free diet. Official sources indicate that the preferred serological test for most patients is the determination of IgA antibodies to tissue transglutaminase. If IgA deficiency is suspected, total IgA should be assessed and, if necessary, IgG tests should be used. [24]

Imaging and endoscopy are selected based on the situation. In cases of acute, non-localized pain and suspected complications, CT scanning is important; in cases of diverticulitis, it helps to clarify the severity of the process; in cases of high risk of inflammatory bowel disease or tumor, colonoscopy is required; and if obstruction or ischemia is suspected, examination should be performed without delay. There is no single test that suits all cases. [25]

Table 4. What examinations are most often needed?

Method	When it is especially useful	What helps to understand
Complete blood count, C-reactive protein, iron or ferritin	for chronic pain, blood in the stool, weakness, weight loss	anemia and signs of inflammation
Fecal calprotectin	in the debate between irritable bowel syndrome and inflammatory bowel disease	probability of inflammation of the mucous membrane
Stool testing for infectious agents	with fever, blood, mucus, severe diarrhea	bacterial or other infection
Serology for celiac disease	for pain, bloating, diarrhea, anemia, deficiencies	probability of celiac disease
Computed tomography	in case of acute pain, complications, suspected diverticulitis, obstruction, ischemia	complications and anatomical cause
Colonoscopy	in case of alarming signs, blood, anemia, high calprotectin	inflammation, tumor, source of bleeding

The table is based on current recommendations for irritable bowel syndrome, fecal calprotectin, infectious diarrhea, celiac disease, diverticulitis, and cancer alertness. [26]

Treatment

The main rule of treatment is not to treat "bowel pain in general," but to address its underlying cause. The symptoms may appear identical, but irritable bowel syndrome requires dietary adjustments, an explanation of the disease mechanism, and medications tailored to the specific bowel pattern. Infections require rehydration and the correct selection of indications for testing and therapy. Diverticulitis requires an assessment of complications. Inflammatory bowel disease requires confirmation of the diagnosis and anti-inflammatory treatment under the supervision of a specialist. [27]

For irritable bowel syndrome, a modern approach begins with patient education, dietary assessment, and identification of dietary triggers. Recommendations support the use of soluble fiber over coarse insoluble fiber, and also allow the use of peppermint oil in some patients. Further therapy depends on the specific condition: if constipation predominates, certain medications are recommended, while others are recommended for diarrhea. Psychotherapeutic methods may be important in cases of significant stress and central pain regulation. [28]

If pain is associated with chronic constipation, pharmacotherapy is selected in a stepwise manner. Joint guidelines from the American Gastroenterological Association and the American College of Gastroenterology in adults strongly recommend polyethylene glycol, followed by linoclotide, plecanatide, and prucalopride after over-the-counter medications have failed. For some patients, fiber, lactulose, senna, magnesium oxide, and lubiprostone are conditionally recommended. This means that drug selection should depend on the symptom profile, availability, and tolerability. [29]

In infectious diarrhea and colitis, fluid replacement remains the mainstay of treatment, while stool examination and antimicrobial therapy are determined based on the clinical picture. If there is blood, mucus, high fever, severe pain, signs of sepsis, or immunodeficiency, the patient requires an in-person assessment and often laboratory verification of the pathogen. Simply attempting to "stop the stool at any cost" without understanding the cause in such cases can be erroneous. [30]

The strategy for diverticulitis has changed in recent years. In immunocompetent patients with a mild, uncomplicated condition, antibiotics may be prescribed selectively rather than automatically to everyone. However, if the patient is immunosuppressed, systemically ill, has complications, or is suspected of having a complicated condition, antibiotic therapy and more active monitoring are mandatory. Therefore, with diverticulitis, it is important not only to relieve pain, but also to determine whether the episode is complicated. [31]

If inflammatory bowel disease, celiac disease, intestinal obstruction, or ischemia are confirmed, self-medication is no longer acceptable. For ulcerative colitis and Crohn's disease, treatment is determined by the severity and location of the inflammation and requires specialized monitoring. For celiac disease, a strict gluten-free diet is key after confirmation of the diagnosis. Intestinal obstruction and ischemia require urgent treatment, as delay increases the risk of necrosis, perforation, and severe complications. [32]

Table 5. Treatment for the most likely cause

Situation	The basic approach	What is important to remember
Irritable bowel syndrome	education, dietary modification, soluble fiber, individual symptomatic therapy	diagnosis is possible without total "ruling out everything"
Chronic constipation	step therapy starting with fiber and osmotic agents	If there are alarming signs, an organic cause needs to be sought.
Infectious colitis	rehydration, if indicated, stool examination and targeted therapy	blood, fever and severe pain require in-person evaluation
Diverticulitis	assessment of complications, pain relief, sometimes antibiotics	Not everyone needs antibiotics for mild, uncomplicated cases.
Inflammatory bowel disease	confirmation of diagnosis, anti-inflammatory therapy under the supervision of a specialist	You can't delay the examination if you have blood tests or are losing weight.
Celiac disease	gluten-free diet after diagnosis	You can't start a diet before serology
Obstruction or ischemia	emergency hospitalization	this is not a home scenario

The table is based on recommendations for irritable bowel syndrome, chronic constipation, infectious diarrhea, diverticulitis, celiac disease, and intestinal emergencies. [33]

What you can and can't do at home

Home monitoring is only appropriate for mild pain without alarming symptoms, when there is no blood in the stool, high fever, persistent vomiting, increasing bloating, weight loss, or severe weakness. In this situation, it is helpful to record how the pain is related to stool, diet, dairy products, legumes, large amounts of rapidly fermentable carbohydrates, stress, and the menstrual cycle. Such a diary is often more helpful than the haphazard use of several medications in a row. [34]

If you're prone to constipation, adequate fluid intake, a gradual increase in fiber, and the use of a safe step-by-step approach to therapy are usually helpful, rather than occasional aggressive attempts to "cleanse the bowels completely." However, if constipation is accompanied by persistent pain, blood, vomiting, or inability to pass gas, home remedies should be discontinued and help sought. [35]

If bloating and pain after eating are prevalent, especially when combined with changes in bowel habits, it may be helpful to discuss irritable bowel syndrome and food triggers with a doctor. Some patients benefit from restricting certain fermentable carbohydrates under the supervision of a specialist, but excessively restrictive diets without a diagnosis and a reintroduction plan can impair nutrition and quality of life. [36]

It is very important not to start a strict gluten-free diet without testing if celiac disease is suspected. Eliminating gluten beforehand may make serological tests and biopsies less informative, making diagnosis more difficult. Therefore, testing should be done first, then a final decision on diet should be made. [37]

With any form of pain that recurs for weeks, disrupts sleep, causes weight loss, is accompanied by blood, or makes stool unpredictable, the goal is not to find the "strongest painkiller," but to identify the source of the symptom. Bowel pain is a situation where time sometimes works in the patient's favor if there is a functional disorder, but against them if the symptom is due to inflammation, tumor, obstruction, or ischemia. [38]

Table 6. When can you observe at home and when you can’t?

Scenario	Home surveillance is acceptable	Need urgent or expedited assistance?
Mild recurring pain without blood or fever	Yes	No
Pain associated with defecation and without alarming signs	Yes, after the initial assessment it is possible	if symptoms worsen or red flags appear
Pain with blood in stool	No	Yes
Pain with vomiting and no gas	No	Yes
Pain with weight loss or anemia	No	Yes
Sudden, very severe pain	No	Yes

The table is based on recommendations for irritable bowel syndrome, symptoms of colorectal cancer, constipation, intestinal obstruction and ischemia. [39]

FAQ

1. Can intestinal pain simply be caused by gas?
Yes, gas formation and distension of the intestinal wall can indeed cause cramping or distending pain, especially with irritable bowel syndrome and constipation. But if the pain is severe, persistent, and accompanied by vomiting, fever, blood, or weight loss, it cannot be attributed solely to gas. [40]

2. How can irritable bowel syndrome be distinguished from inflammatory bowel disease?
Irritable bowel syndrome is characterized by pain associated with defecation and changes in stool without signs of systemic inflammation. Inflammatory bowel disease is more characterized by blood in the stool, weight loss, nocturnal symptoms, anemia, and elevated fecal calprotectin. Definitive differentiation often requires laboratory evaluation and sometimes colonoscopy. [41]

3. Is a colonoscopy always necessary for bowel pain?
No. For typical irritable bowel syndrome without alarming symptoms, the modern approach does not require mandatory colonoscopy for everyone. However, if there is blood in the stool, anemia, weight loss, high calprotectin, persistent changes in stool, or an increased risk of cancer, endoscopy may be necessary. [42]

4. Can constipation cause severe pain?
Yes, it can, especially if there is significant bloating, constipation, and hard stools. But if constipation is accompanied by vomiting, loss of gas, blood, persistent increasing pain, or weight loss, one should consider an obstruction or other organic cause, not just functional constipation. [43]

5. Is pain in the lower left abdomen always caused by the intestines?
No. Although this location is very typical with diverticulitis, similar pain can have other causes. Therefore, accompanying symptoms are important: temperature, stool characteristics, urinary symptoms, examination findings, and, if necessary, imaging. [44]

6. Should I immediately eliminate gluten if I have bloating and pain?
No, I need to be examined first. If celiac disease is suspected, serological tests should be performed before switching to a gluten-free diet; otherwise, the diagnosis may be less accurate. [45]

7. What are the most alarming symptoms of bowel cancer?
The most important include blood in the stool, persistent changes in bowel habits, persistent abdominal pain or cramps, unexplained weight loss, and anemia. These signs do not automatically indicate a cancer diagnosis, but they do require investigation. [46]

8. Can bowel pain be treated with painkillers alone?
No, because pain relief doesn't address the underlying cause. For functional pain without warning signs, symptomatic measures are possible, but in cases of diverticulitis, inflammatory bowel disease, obstruction, ischemia, or tumor, simply trying to "mask" the symptom can delay proper diagnosis. [47]

9. When is a stool test necessary for intestinal pain?
When pain is combined with diarrhea, especially with fever, blood, mucus, severe cramping, immunodeficiency, or epidemiological risk. In these situations, a stool test helps identify the pathogen and choose the right treatment strategy. [48]

10. Which test is most often helpful in distinguishing functional pain from inflammation?
Fecal calprotectin is very useful in practice. It doesn't replace all other methods, but it does help determine whether there is reason to suspect inflammatory bowel disease and whether endoscopy is necessary. [49]

Conclusion

Bowel pain is a symptom with a very wide range of causes: from irritable bowel syndrome and constipation to infectious colitis, diverticulitis, inflammatory bowel disease, celiac disease, obstruction, ischemia, and colorectal cancer. The key challenge in modern diagnostics is not to prescribe the same set of tests for everyone, but to quickly determine the correct route based on the combination of pain, stool, systemic symptoms, and warning signs. [50]

The most important practical guidelines are simple: pain associated with defecation and without warning signs is often functional; pain accompanied by blood, weight loss, anemia, nocturnal symptoms, fever, vomiting, lack of gas, or sudden onset requires a more serious approach and often urgent care. This is why, with intestinal pain, it is not the sensation itself that needs to be treated, but its cause. [51]