Last reviewed: December 2023

Next review date: December 2026

Man with stomach cramp standing next to toilet

Diarrhoea is a common symptom of Crohn’s and Colitis. You may continue to have diarrhoea even when your Crohn's or Colitis is under control. 

This information is for anyone with Crohn’s or Colitis (including Microscopic Colitis) who has diarrhoea. It may also be useful for those involved in their care. This information covers:

  • Why you might have diarrhoea if you have Crohn’s or Colitis
  • Some of the things you can try to manage your diarrhoea
  • How what you eat and drink can affect diarrhoea

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  • Key facts about diarrhoea
    • Diarrhoea is when you have a loose or liquid poo three or more times a day, or more often than is normal for you. It is one of the most common symptoms of Crohn’s and Colitis.
    • Diarrhoea might be due to a flare-up of your Crohn’s or Colitis. But there are other factors that may be causing it or making it worse.
    • There are several medicines that can help relieve diarrhoea. Which one you take will depend on the cause of your diarrhoea.
    • These medicines might not be suitable for everyone. Always check with your IBD team or pharmacist first.
    • If you have diarrhoea, you will lose more water than usual in your poo. So it is important to drink plenty of fluids.
  • Is my poo normal?

    The Bristol Stool (Poo) Chart can be used to assess your poo. The 7-point scale helps describe the shape and texture of your poo. If your poo looks like types 1 or 2, it could mean that you have constipation. Experts generally consider types 3 and 4 to be healthy poos. Type 5 is considered healthy going towards diarrhoea. And types 6 or 7 suggest that you have diarrhoea.

  • What is diarrhoea?

    Diarrhoea is when you have a loose or liquid poo three or more times a day, or more often than is usual for you.

    Diarrhoea is one of the main symptoms of Crohn’s Disease, Ulcerative Colitis and Microscopic Colitis. About 8 in every 10 people with the conditions have diarrhoea at some point.

    In people with Crohn’s or Colitis diarrhoea can be mixed with mucus, pus and blood. You may feel that you need to rush to the toilet. This is known as urgency. Or you may experience bowel incontinence.

    Find out more about Bowel incontinence and urgency.

  • Causes of diarrhoea

    The small bowel absorbs the useful nutrients from what you have eaten. Then the liquid and non-digestible parts of food move into your colon. Usually, the colon absorbs most of the water, and the leftover waste forms a solid poo. This collects in the last part of the colon and the rectum before passing out of the body when you have a poo.

    During a flare-up the cells that line the bowel become inflamed. This means that the bowel cannot absorb all the nutrients and water. This can cause watery poo, the need to poo more often and to get to the toilet quickly.

    So, your diarrhoea might be due to a flare-up of your condition. But there are other factors that may be causing it or making it worse. These include:

    Side effects of your Crohn’s or Colitis medicines

    5-ASAs (aminosalicylates) such as mesalazine can cause diarrhoea. Some immunosuppressants, including infliximab, mercaptopurine, and methotrexate, can also cause diarrhoea. It can be hard to tell if it is your condition or your treatment causing diarrhoea. Speak to your IBD team if you’re not sure what may be causing your symptoms.

    Side effects of other medicines

    Diarrhoea might also be a side effect of some medicines that you may be taking for other conditions. For example, acid-lowering treatments, such as omeprazole and lansoprazole, and antibiotics can cause diarrhoea. You can check the information leaflet that comes with your medicine to see if diarrhoea is a side effect.

    Colectomy and ileo-rectal anastomosis

    In this surgery the colon is removed and the end of the small bowel (terminal ileum) is attached to the rectum. Because you no longer have a colon to absorb water, your poo may be quite watery. You may have to go to the toilet many times during the day and night.

    Our information Surgery for Crohn’s Disease and Surgery for Ulcerative Colitis have more details about types of surgery for Crohn’s and Colitis.

    Bile acid malabsorption (BAM)

    Bile acids help you to digest fats. The liver makes bile acids when you eat and releases them into the small bowel. Most of the bile acids are re-absorbed in the last part of the small bowel, and returned to the liver. But, if part of your small bowel is inflamed or has been removed the bile acids are not re-absorbed. So, much higher levels of bile acids pass into the colon. This irritates the lining of the colon, which draws water into the colon causing diarrhoea.

    Reduced fat absorption

    If bile acid malabsorption is severe, you may not be able to digest fats from your food. So, the fats pass into your colon, causing your poo to become fatty. This is sometimes called steatorrhea. Fatty poo is greasy and runny and often smelly. It may float, so can be difficult to flush away.

    Iron supplements

    If you have anaemia you may have iron supplements. Iron supplements usually cause constipation. But they can cause diarrhoea in some people.

    Irritable Bowel Syndrome (IBS)

    People sometimes mistake IBS for Inflammatory Bowel Disease (IBD), but it is a different condition. Like Crohn's and Colitis, IBS can cause tummy pain, bloating, and loose or watery poo. But IBS does not cause inflammation of the bowel or bleeding. Some people with Crohn’s or Colitis develop IBS-like symptoms even when their Crohn's or Colitis is inactive.

    Diet and food

    Some people find that what they eat has little effect on their symptoms. Others find that certain foods trigger symptoms, and cutting down those foods helps. You could use a food diary or app to find out if any foods seem to affect your symptoms. It’s a good idea to discuss possible triggers with your IBD team or dietitian before making any big changes to your diet.

    Changes in symptoms after eating certain foods does not always mean that your condition is flaring up. Food can sometimes trigger symptoms in people without Crohn’s or Colitis.


    It is important not to cut foods out of your diet without talking to your dietitian or IBD team. It could mean you miss nutrients that your body needs.


    See our Food information for more on diet.


    Diarrhoea can be a sign of a tummy infection, such as gastroenteritis or Clostridium difficile.

    Small-intestinal bacterial overgrowth (SIBO)

    Small-intestinal bacterial overgrowth (SIBO) is a condition where there are more bacteria in the small bowel than usual. These extra bacteria can cause symptoms such as diarrhoea, weight loss and malnutrition. This overgrowth occurs when food moves through the gut more slowly than usual. SIBO is often associated with Crohn’s and Colitis.


    Mental health problems, like stress, can have a negative effect on gut symptoms.

  • Managing diarrhoea

    Treatment for diarrhoea will depend on the cause. Often, the first step in managing diarrhoea is to get your Crohn’s or Colitis as well controlled as possible. Reducing the inflammation in your bowel should help to improve gut symptoms.

    Medicines to treat diarrhoea

    Medicines to control diarrhoea are often called anti-diarrhoeal medicines. There are different types of anti-diarrhoeal medicines. Which one you try will depend on a number of things, including the cause of your diarrhoea. 

    Antimotility medicines

    Antimotility medicines are a common type of anti-diarrhoeal medicine. Your doctor or IBD team may suggest these if you keep getting diarrhoea.

    Antimotility medicines slow down you’re the movement of food through your gut. This means that food takes longer to pass through your gut. This allows more water to be absorbed from your bowel into your body. So, your poo becomes firmer, and you need to poo less often.

    Loperamide is a commonly used antimotility medicine.


    Always check with your IBD team before taking an antimotility medicine. 

    • Do not take an antimotility medicine if you are in a flare-up, you have a high temperature or you have blood in your poo. This can lead to a serious complication called toxic megacolon. This is a widening or swelling of the colon that may cause perforation.
    • You may not be able to take these medicines if you have a narrowing of the bowel called a stricture.


    Bulk-forming laxatives

    Bulk-forming laxatives are often used to treat constipation. But your doctor may also recommend them for diarrhoea. These include ispaghula and sterculia, which come as granules that you mix with water. They absorb water in the bowel, which makes your poo bulkier. This helps your bowels to keep moving and working normally.

    Check with your pharmacist or IBD team before taking a bulk forming laxative. Do not take bulk-forming laxatives if you have a narrowing of the bowel, called a stricture.


    Some drug manufacturers advise against using antimotility medicines or laxatives in people with acute or severe Crohn’s or Colitis. Your doctor or nurse may have prescribed these for you. If so, they will have considered the advantages and disadvantages of you taking them. Speak to your IBD team if you have any concerns about taking them.


    Antispasmodic medicines

    These medicines relax the muscles in your gut. This eases painful cramps or spasms. They include:

    • Mebeverine
    • Hyoscine butylbromide
    • Alverine citrate

    Antispasmodic medicines can be useful in people with IBS-like symptoms.

    Bile acid binders

    Bile acid binders can be used for diarrhoea caused by bile acid malabsorption. They bind to bile acids in the small bowel. This stops the bile acids reaching the large bowel and causing diarrhoea. The main bile acid binders include colestyramine and colestipol. These come in powder or granule form and can be mixed with water, juice or soft food. A tablet form called colesevelam is also available.

    Side effects include bloating and discomfort in the tummy, feeling sick and constipation. They can affect the absorption of other medicines that you might be taking. So, it is important to check with your IBD team or pharmacist how to manage taking them alongside each other.

    Does what I eat or drink affect diarrhoea?

    Some people find that what they eat or drink has no effect on their diarrhoea. Others find that changing what they eat and drink helps. You could use a food diary or app to find out if any foods seem to affect your symptoms.

    Foods or drinks that might make diarrhoea worse in people with or without Crohn’s or Colitis include:

    • Caffeine
    • Alcohol
    • Artificial sweeteners
    • Liquorice

    Gluten sensitivity

    Gluten is a protein that’s found in wheat, barley, rye and oats, or foods that contain them. If your diarrhoea is worse after eating foods containing gluten you may be sensitive to gluten. About 1 in 4 people with Crohn’s or Colitis say they are sensitive to gluten and avoid it in their diet. This might improve symptoms for some people, but there is not enough evidence to recommend it for everyone with Crohn’s or Colitis.

    Sometimes, gluten sensitivity is a sign of coeliac disease. You can ask your GP for a blood test to check for this. Note that you should include gluten in your diet when you have the blood test. This is because avoiding it could lead to an incorrect result. More information about coeliac disease is available at www.coeliac.org.uk.


    Current guidelines say that unless you have a narrowing (stricture) in your gut, you do not need to limit your fibre intake when your condition is under control.  

    But for some people high-fibre foods can make diarrhoea worse. And during flare-ups, it might help to reduce the amount of fibre you eat. Eat fibre that is easy to digest, like well-cooked, peeled vegetables, bananas, melons, or fruit juice.

    Fibre is an important part of the diet, as it helps the bowel to function normally. So talk to your IBD team or dietitian before making changes to the fibre in your diet. You can try adding fibre back into your diet once your flare-up has settled.

    Lactose intolerance

    Lactose is a sugar found in dairy products like milk, cream and cheese. An enzyme called lactase in the lining of your small bowel usually breaks it down so your body can absorb it.

    If lactose is not broken down, your body cannot absorb it. This is called lactose malabsorption. It might not cause any problems at all. But it can cause symptoms like diarrhoea, bloating, wind, tummy pain and feeling sick. If it causes symptoms, it’s called lactose intolerance.

    In the UK, around 8 in every 100 people are lactose intolerant. People with Colitis have a similar risk of being lactose intolerant as the general population. But people with Crohn’s may have a slightly higher risk. Some people with Crohn’s or Colitis only get symptoms of lactose intolerance during a flare-up.


    Symptoms of lactose intolerance may be like flare-ups. So it’s important to talk to your IBD team before cutting out lactose.


    Your IBD team can help you find out if you are lactose intolerant. If so, you can manage symptoms by following a low lactose or lactose-free diet. Some medicines also contain lactose. But do not stop taking any prescribed medicines without checking with your doctor or IBD team.


    It is important not to cut foods out of your diet without talking to your dietitian or IBD team. It could mean you miss nutrients that your body needs.


    For more information on healthy eating with Crohn’s or Colitis see our booklet on Food.


    • Many people are sensitive to caffeine, so try opting for decaf coffee, tea, and other drinks.
    • You may wish to reduce your consumption of alcohol, as this can have a laxative effect.
    • Drinks made with artificial sweeteners such as sorbitol can also cause diarrhoea.
    • Plain water or squash is a good option.
  • Dehydration

    If you have diarrhoea, you will lose more water than usual in your poo. So it is important to drink plenty of fluids. This could be drinks like water or diluted squash. Keep drinking small amounts of fluids often. You might need to increase the levels of salts and sugar in your body, as well as water. Oral rehydration solutions (ORS) are powders or tablets that are dissolved in water. They help the body replace water, salts, and sugar. You can buy oral rehydration solutions from most supermarkets and pharmacies. Your pharmacist can recommend a rehydration solution that is right for you.

    If you have a high output stoma or short bowel syndrome, speak to your GP or IBD team to find out what type of rehydration would work best for you. You are more likely to need more salt than most store-bought rehydration solutions provide. Your GP or IBD team may recommend drinking an oral rehydration solution with a higher salt (sodium) level.

    For more information on how to recognise and manage dehydration see our separate information resource: Dehydration.

  • Diarrhoea with a stoma

    If you have an ileostomy the contents of your bowel, called your stoma output, is usually quite liquid – like a paste or porridge. The output of a colostomy is usually semi-solid and can be like normal poo. But this varies depending on how much of your large bowel you have left. If you do not have much large bowel left, the output will be more liquid. The output of your stoma will vary and may increase or become more watery than usual if:

    • You have a tummy bug
    • You are taking certain medicines, like antibiotics
    • You have eaten or drunk something that makes your stoma more active

    If this happens, keep drinking. You are likely to need rehydration therapy. Ask your pharmacist or IBD team. Eating foods that thicken your stoma output might help. Starchy foods like white rice, bread, pasta, noodles and peeled cooked potatoes are good. If your diarrhoea does not improve, your stoma nurse might suggest an anti-diarrhoeal medicine.

    For more information see Living with a Stoma.

  • Skin care

    Frequent diarrhoea can cause sore skin around your bottom. Frequent washing and wiping of your bottom can also irritate the skin. The following tips may help prevent sore skin:

    • Moist toilet paper, wet wipes or damp cotton wool can be more comfortable than dry toilet paper. Some toilet wipes contain alcohol and other chemicals which can irritate the skin. Try to choose alcohol-free brands or products for sensitive skin. Take care to dispose of wet wipes properly.
    • Whenever possible, wash around your bottom after you have had a poo. Avoid using flannels and sponges as they can be rough and are difficult to keep clean. Avoid using disinfectants or antiseptics as these can sting and you may be sensitive to the chemicals in them. Plain warm water is best.
    • Avoid using products with strong perfume. Instead use non-scented soap or a no-rinse cleanser. No-rinse cleansers avoid the need for soap and water, which may dry the skin.
    • Dry the area with soft toilet paper or a soft towel. Be very gentle and pat rather than rub. If your skin is very sore, you could try using a hairdryer on a low heat setting to dry the skin.
    • You can use barrier products to protect the skin. Barrier products act to reduce the skin’s contact with poo. They usually contain substances such as zinc oxide or dimeticone. There is currently not enough evidence to show that one product works better than another. Barrier products are available in different forms such as creams, ointments, and wipes.
      Check before using them as some people are allergic to some of the ingredients, such as lanolin. Use a little at a time, as too much can stop the skin from breathing and can make the area sweaty and uncomfortable. Always make sure you wash off the old layer before applying more.
    • Try to allow air to get to the area. Wear cotton underwear and avoid synthetic material to allow the skin to breathe. Try not to wear tight-fitting clothes such as tights and tight trousers.

    If your skin continues to feel sore or is broken, talk to your doctor or IBD team.

  • Managing smells

    If you are worried about smells, you may wish to try odour neutralisers. These help to get rid of smells rather than just mask them. Products available include room sprays and toilet deodorisers.

  • Other organisations
  • About this information

    We follow strict processes to make sure our information is based on up-to-date evidence and easy to understand.

    Please email us at evidence@crohnsandcolitis.org.uk if:

    • You have any comments or suggestions for improvements
    • You would like more information about the sources of evidence we use
    • You would like details of any conflicts of interest

    You can also write to us at Crohn’s & Colitis UK, 1 Bishop Square, Hatfield, AL10 9NE, or contact us through our Helpline: 0300 222 5700


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