What Is Ischemic Colitis? The Colon Blood Flow Problem That Usually Heals on Its Own — and the Signs That Mean Trouble
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: Key Facts About Ischemic Colitis
Ischemic colitis is a temporary reduction in blood flow to part of the colon, which can damage and swell its tissue. Symptoms include belly pain, often on the left, bright red or maroon blood in the stool and diarrhea. It mostly affects adults over age 60. Most cases improve in 2 to 3 days with treatment, though some need surgery. [1] [2]
What the research says
Surgery is the exception, not the rule. A systematic review and meta-analysis pooling 19 studies and 12,420 patients found that about 15% of people with ischemic colitis needed surgery (95% CI 13%–16%), and about 15% had right-sided disease (95% CI 14%–17%), which was linked to higher mortality and more surgery (Qian et al., World J Surg, 2024) [3]
Irritable bowel syndrome is linked to a higher risk. A meta-analysis of 3 cohort and 8 case-control studies found that people with irritable bowel syndrome had higher odds of ischemic colitis (pooled odds ratio 2.50, 95% CI 2.00–3.14) (Wongtrakul et al., Minerva Gastroenterol, 2022) [4]
Medicine-related cases were reversible in trials. In a systematic review of alosetron (a medicine for severe diarrhea-predominant IBS), ischemic colitis occurred in 0.15% of alosetron users versus 0.0% on placebo (p = 0.03), and all 19 alosetron-using patients with ischemic colitis had reversible colitis without long-term sequelae (Chang et al., Am J Gastroenterol, 2006) [5]
What is ischemic colitis?
Ischemic colitis happens when blood flow to part of the large intestine, called the colon, is temporarily reduced. Ischemia simply means tissue is getting less blood than it needs.
The colon can be affected anywhere along its length, but ischemic colitis is most common in the upper left segment. That is why it most often causes pain on the left side of the belly.
When blood flow slows down, the cells in the colon do not get enough oxygen. This can result in damage and swelling of the colon's tissues. The reduced blood flow is usually caused by narrowing of the blood vessels that supply the colon or by low blood pressure. [1]
The condition can be hard to diagnose because it is easily confused with other digestive problems — especially inflammatory bowel disease (IBD). You may need medicine to treat it or prevent infection, or surgery if your colon has been damaged. Most often, however, ischemic colitis heals on its own. [1]
What are the symptoms of ischemic colitis?
Symptoms of ischemic colitis develop from the colon losing oxygen, and they usually involve the belly and the stool. [1]
Symptom | What it looks like |
Belly pain, tenderness, or cramping | Can happen suddenly or build up over time; most often on the left side |
Bright red or maroon blood in stool | Or, at times, passing blood alone without stool |
Urgency to move the bowels | A strong, pressing need |
Diarrhea | Loose or frequent stools |
Nausea | Stomach upset |
Left-sided vs. right-sided colitis
Most cases affect the left side of the colon and follow a milder course. Right-sided colitis is less common but carries a higher risk of serious complications. People with right-sided colitis more often have underlying medical conditions, such as high blood pressure, atrial fibrillation, and kidney disease. They more often have to undergo surgery, and they have a higher risk of death. [1]
When should you see a doctor?
Seek immediate medical care if you have sudden, severe pain in your belly area. Pain that makes you so uncomfortable that you cannot sit still or find a comfortable position is a medical emergency.
Contact a healthcare professional if you have symptoms that worry you, such as bloody diarrhea. Early diagnosis and treatment can help prevent serious complications. [1]
What causes ischemic colitis?
Ischemic colitis happens when blood flow to the colon drops, and the exact reason for that drop is not always clear. But several factors can increase the risk. These include:
A buildup of fatty deposits on the walls of an artery, called atherosclerosis
Low blood pressure (hypotension) associated with dehydration, heart failure, surgery, trauma, or shock
A bowel obstruction caused by a hernia, scar tissue, or a tumor
Surgery involving the heart or blood vessels, or the digestive or gynecological systems
Medical conditions that affect the blood, including lupus, sickle cell anemia, or inflammation of the blood vessels (called vasculitis)
Cocaine or methamphetamine use
Rarely, colon cancer
Can medicines cause ischemic colitis?
Yes — the use of certain medicines can also lead to ischemic colitis, though this is rare. [1]
Medicine group | Examples |
Heart and migraine medicines | Some drugs that constrict blood vessels |
Hormone medicines | Estrogen and birth control |
Antibiotics | Various antibiotic treatments |
Pseudoephedrine | A decongestant found in cold medicines |
Opioids | Pain medicines |
Illicit drugs | Cocaine and methamphetamines |
Irritable bowel syndrome medicines | Certain IBS treatments |
Chemotherapy | Cancer treatment medicines |
Who is more likely to get ischemic colitis?
A number of different factors can increase a person's chances of developing ischemic colitis. [1]
Risk factor | Why it matters |
Age | Mostly happens in adults older than 60. In a young adult, it may signal a blood-clotting issue or vasculitis |
Sex | More common in women |
Clotting problems | Conditions like factor V Leiden or sickle cell disease may increase risk |
High cholesterol | Can lead to atherosclerosis |
Reduced blood flow | From heart failure, low blood pressure, or shock; also affected by diabetes or rheumatoid arthritis |
Previous abdominal surgery | Scar tissue may cause reduced blood flow |
Heavy exercise | Marathon running can reduce blood flow to the colon |
Surgery | Involving the heart, digestive, or gynecological systems |
What complications can ischemic colitis cause?
Ischemic colitis usually gets better on its own within 2 to 3 days. In more-serious cases, complications can include three main problems. [1]
Tissue death, also called gangrene, can result from diminished blood flow.
A hole in the intestine, also called a perforation, can form, along with persistent bleeding.
The colon can also develop a blockage, called an ischemic stricture, when damaged tissue scars and narrows the bowel.
How is ischemic colitis diagnosed?
Ischemic colitis is often confused with other conditions because their symptoms overlap, especially inflammatory bowel disease (IBD). Based on your symptoms, a healthcare professional may recommend several tests. [2]
Test | What it does |
Abdominal CT scan | Provides images of the colon that help rule out other disorders, such as IBD |
Colonoscopy | Provides detailed images of the colon; can diagnose ischemic colitis, check for cancer, and show how well treatment worked. A tissue sample (biopsy) may be collected |
Stool analysis | Rules out infection as the cause of symptoms |
Follow-up colonoscopies may also be scheduled to monitor healing and look for complications.
How is ischemic colitis treated?
Treatment depends on the severity of the condition. In mild cases, symptoms often diminish in 2 to 3 days. For mild ischemic colitis, a healthcare professional may recommend: [2]
Antibiotics to prevent infections
Intravenous fluids if the person is dehydrated
Treatment for any underlying medical condition, such as congestive heart failure or an irregular heartbeat
Stopping medicines that constrict the blood vessels, such as migraine or hormone medicines and some heart medicines
Bowel rest, which may involve temporarily getting nutrients from a feeding tube
When is surgery needed?
If symptoms are serious or the colon has been damaged, surgery may be needed to:
Remove dead tissue
Repair a hole in the colon
Remove part of the colon that has narrowed because of scarring and is causing a blockage
The likelihood of surgery is higher if the person has an underlying condition such as heart disease, atrial fibrillation, or kidney failure. [2]
How can you prevent ischemic colitis?
Since the cause is not always clear, there is no certain way to prevent the disorder. Most people who have ischemic colitis recover quickly and may never have another episode.
To help prevent recurrent episodes, some healthcare professionals recommend stopping any medicine that might cause the condition. Staying hydrated is also important, especially during vigorous outdoor activities and for people living in warm climates. A test for clotting problems may be recommended as well, especially if no other cause for the ischemic colitis is apparent. [1]
How can you prepare for a doctor's appointment?
Go to the emergency room if you have severe stomach pain that makes you so uncomfortable that you cannot sit still. You may be referred for immediate surgery to diagnose and treat your condition.
If your symptoms are mild and happen only occasionally, call your healthcare team for an appointment. After the first evaluation, you may be referred to a doctor who specializes in digestive disorders, called a gastroenterologist, or a surgeon who specializes in blood vessel disorders, called a vascular surgeon. [2]
To prepare, be aware of any pre-appointment restrictions, such as not eating after midnight the night before. Write down your symptoms, including when they started and how they have changed. Write down your key medical information, make a list of all medicines, vitamins, and supplements, and write down your questions.
Helpful questions to ask include:
What is the most likely cause of my condition?
What tests do I need?
How can I best manage my other health conditions together?
If I need surgery, what will recovery be like?
How will my diet and lifestyle change after surgery?
What follow-up care will I need?
Your provider will likely ask:
When did your symptoms begin?
Have they been continuous or occasional?
How severe are they?
Where do you feel them most?
What makes them better or worse?
Conclusion and next steps
Ischemic colitis is a condition in which reduced blood flow temporarily starves part of the colon of oxygen, causing tissue damage and swelling. Although the name sounds alarming, most cases improve on their own within 2 to 3 days with simple measures such as antibiotics, IV fluids, bowel rest, and stopping medicines that constrict blood vessels.
The warning signs deserve attention, however. Sudden, severe belly pain — especially pain so bad that you cannot sit still — is a medical emergency. Bloody diarrhea, right-sided pain, and underlying heart disease, atrial fibrillation, or kidney failure all raise the stakes and may point toward surgery.
Because the symptoms overlap with inflammatory bowel disease and other digestive problems, diagnosis usually requires a CT scan, colonoscopy, and stool tests. If you or someone you care about has bloody stools or severe belly pain, contact a healthcare professional promptly. Early evaluation is the best protection against serious complications.
Talk with a healthcare professional. If you have belly pain with bloody diarrhea, pain that keeps you from getting comfortable, or symptoms that return after a previous episode, contact your healthcare team right away. For more plain-language guides on digestive and blood vessel health, explore the related articles on Rinnit.com.
Frequently Asked Questions
What is ischemic colitis?
Ischemic colitis is a condition that occurs when blood flow to part of the colon (large intestine) is temporarily reduced. The reduced oxygen can damage and swell the colon's tissues. It is also called colonic ischemia.
What are the main symptoms?
The most common symptoms are belly pain, tenderness, or cramping (most often on the left side), bright red or maroon blood in the stool, urgency to pass stool, diarrhea, and nausea.
Does ischemic colitis go away on its own?
In most cases, yes. Symptoms usually diminish within 2 to 3 days, often with antibiotics and IV fluids. Most people recover quickly and may never have another episode.
What causes ischemic colitis?
Reduced blood flow to the colon, most often from narrowed blood vessels (atherosclerosis) or low blood pressure. Other causes include bowel obstruction, certain surgeries, blood disorders like lupus and sickle cell disease, and certain medicines.
Is ischemic colitis an emergency?
Ischemic colitis can be. Sudden, severe belly pain that makes it impossible to sit still or find a comfortable position is a medical emergency. Bloody diarrhea also warrants prompt medical evaluation.
When is surgery needed?
Surgery may be needed if symptoms are serious or the colon is damaged — to remove dead tissue, repair a hole in the colon, or remove a scarred, narrowed section causing a blockage. People with heart disease, atrial fibrillation, or kidney failure are more likely to need surgery.
Can medicines cause ischemic colitis?
Yes, rarely. Medicines that can contribute include some heart and migraine medicines, hormone medicines such as estrogen and birth control, antibiotics, pseudoephedrine, opioids, certain IBS medicines, and chemotherapy.
How is ischemic colitis diagnosed?
A provider asks about symptoms and orders tests such as blood tests, stool tests and a CT scan of the belly. A colonoscopy may be used to look at the lining of the colon and confirm the diagnosis.
Who is most likely to get ischemic colitis?
It mostly affects adults older than 60. In a younger adult, it may point to a blood-clotting problem or inflamed blood vessels (vasculitis), so a provider may order extra tests.
Can ischemic colitis come back?
It can happen again in some people. Stopping medicines that may have caused it, staying well hydrated and managing heart and blood vessel conditions can help lower the risk. Ask your provider which steps fit you.
Related Reading
References
Mayo Clinic Staff. Ischemic colitis – Symptoms and causes. Mayo Clinic. Updated November 7, 2024. https://www.mayoclinic.org/diseases-conditions/ischemic-colitis/symptoms-causes/syc-20374001
Mayo Clinic Staff. Ischemic colitis – Diagnosis and treatment. Mayo Clinic. Updated November 7, 2024. https://www.mayoclinic.org/diseases-conditions/ischemic-colitis/diagnosis-treatment/drc-20374005
Qian W, Bruinsma J, Mac Curtain B, et al. Surgical prevalence and outcomes in ischemic colitis: A systematic review and meta-analysis. World J Surg. 2024;48(4):943-953. PMID 38441288. https://doi.org/10.1002/wjs.12123
Wongtrakul W, Charoenngam N, Ungprasert P. The association between irritable bowel syndrome and ischemic colitis: a systematic review and meta-analysis. Minerva Gastroenterol (Torino). 2022;68(4):470-474. PMID 34547858. https://doi.org/10.23736/S2724-5985.21.02957-0
Chang L, Chey WD, Harris L, et al. Incidence of ischemic colitis and serious complications of constipation among patients using alosetron: systematic review of clinical trials and post-marketing surveillance data. Am J Gastroenterol. 2006;101(5):1069-79. PMID 16606352. https://doi.org/10.1111/j.1572-0241.2006.00459.x
Moszkowicz D, Mariani A, Trésallet C, et al. Ischemic colitis: the ABCs of diagnosis and surgical management. J Visc Surg. 2013;150(1):19-28. PMID 23433833. https://doi.org/10.1016/j.jviscsurg.2013.01.002
Medical disclaimer
This article is for informational purposes only and is not medical advice. Always consult a qualified healthcare professional for diagnosis and treatment decisions.
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