All about Crohn's and Colitis

Last reviewed: October 2019

Currently under review

This information is for people who are new to Crohn's or Colitis. It covers the basics you need to know about the conditions. This information is available to download in English, Bengali, Gujarati, Polish, Punjabi, Urdu and Welsh.

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  • Crohn's and Colitis
    Crohn’s Disease and Ulcerative Colitis are Inflammatory Bowel Diseases (IBDs). They can cause painful sores (ulcers) and inflammation (swelling) in your gut.

    Crohn’s and Colitis are lifelong conditions, which means you will always have it. But that doesn’t mean you will always feel unwell. Treatment like medicines and surgery can help you feel a lot better.

    There is another type of IBD called Microscopic Colitis, which usually gets better after treatment. 

    It’s something you’ll have to learn to adapt to – and you will. Don’t let your mind run riot, and know that things will get better if you let them. Everyone goes through their own stuff in life; if you embrace it, everything becomes a lot easier.

    Living with Crohn's

  • The digestive system

    The gut

    The gut takes food and nutrients into your body, and carries poo out. The gut starts at your mouth, when you eat, and ends at your bottom (anus), where poo passes out of your body.

    The gut is also called the digestive system, because it digests (breaks down) food.

    The bowel

    The bowel is an important part of the gut. It is a long tube, coiled up inside you, made up of your small bowel (small intestine), colon and rectum. The colon and rectum are called the large bowel (large intestine). At the end of your rectum is your anus, where poo passes out of your body.

    The walls of your bowel have layers. The layers take in nutrients from food, and help get rid of waste.

    Digestion graphic

  • Types of Crohn's and Colitis

    Crohn’s Disease

    Crohn’s Disease is inflammation anywhere in the gut, from your mouth to your anus. Although Crohn’s is called an Inflammatory Bowel Disease, any part of the gut can be affected, not just your bowel. All layers of the gut can be inflamed.

    ‘Crohn’s Colitis’ is a type of Crohn’s Disease where only the large bowel is inflamed. This is because ‘colitis’ means inflammation of the large bowel. It doesn’t mean you have both Crohn’s Disease and Ulcerative Colitis.

    Ulcerative Colitis

    Ulcerative Colitis is inflammation and ulcers in the large bowel. It can be anywhere from your colon to your anus. Only the inner lining is inflamed.

    If only your rectum is inflamed, it’s called proctitis.

    Microscopic Colitis

    Microscopic Colitis is inflammation of the large bowel. Unlike Ulcerative Colitis, Microscopic Colitis does not cause ulcers, and there is no blood in the poo. Doctors have to use a microscope to see the inflammation.

    Uncertain diagnosis

    If your doctor says you have Indeterminate Colitis or IBDU (Inflammatory Bowel Disease Unclassified) it’s not certain whether you have Crohn’s or Colitis.

  • Who has Crohn's and Colitis?
    In the UK, about 1 in 123 people have Crohn’s or Colitis. That’s 500,000 people.

    Crohn’s Disease and Ulcerative Colitis can start at any age, but they usually start before you’re 30.

    Microscopic Colitis is more common in women and usually starts after 50.

  • Feeling unwell

    Everyone is different: some people with Crohn’s or Colitis feel well most of the time, other people take longer to find a treatment that’s right for them.

    Not everyone feels the same, and how you feel can change over time.

    Crohn’s and Colitis can cause:

    • Cramping pains
    • Frequent and urgent diarrhoea, sometimes with blood and thick liquid (mucus)
    • Swollen joints
    • Mouth ulcers
    • Tiredness
    • Lack of iron (anaemia)
    • Losing weight and not wanting to eat
    • Inflamed eyes

    If you have Crohn’s, you may also get cracks (fissures) in the skin around your bum. Sometimes your gut can become narrow (strictures). Your IBD team are there to help - talk to them if you notice anything unusual for you.


    Times when you feel unwell are called flare-ups.

    Taking your medicines regularly, even when you feel better, can help stop flare-ups happening.

    Your doctor (gastroenterologist) and the rest of your IBD team are there to support you. Ask your hospital if they have an IBD nurse you can speak to if you need help in between doctors appointments.


    Remission is when your Crohn’s or Colitis is being controlled well. You should continue to take your medicines even when you feel better.

    A lot of people can still feel tired even when their Crohn’s or Colitis is under control, so it’s important to rest when you need to.

    If you still feel unwell in your gut, even when your doctor says you’re in remission, you may also have a condition
    called Irritable Bowel Syndrome (IBS). Inflammatory Bowel Disease (IBD) and IBS are different, but you can have both at the same time.

    IBS is very common, and can cause tummy pain, bloating, diarrhoea and constipation. But unlike Crohn’s and Colitis, there is no inflammation, or blood in the poo.

    If you have IBS as well as Crohn’s or Colitis, you may need treatment for both.

  • Causes of Crohn's and Colitis

    Crohn’s and Colitis happen when the body’s immune system goes wrong.

    Usually, the immune system protects the body. In Crohn’s and Colitis, the immune system starts attacking the body.

    We don’t know why the immune system attacks the body. It is probably caused by a mix of genes and the environment (like germs, diet, smoking and stress).

  • Tests

    To find out if you have Crohn’s or Colitis, you probably had lots of tests. The same tests help your doctors check (monitor) your health and find the best treatment for you.

    Tests for Crohn’s and Colitis include:

    Blood tests

    Blood tests check for inflammation, signs of infection, and low iron levels. They can also show if you are getting enough nutrients and vitamins.

    Poo tests

    Poo tests check for infections and inflammation.


    Your doctor looks at your gut with a tiny camera on a long, thin tube (endoscope). The tube goes through your mouth (gastroscopy) or your bottom (sigmoidoscopy or colonoscopy).

    The doctor can take tiny pieces of your gut (tissue biopsy) to check for inflammation.

    Ultrasound, CT and MRI scans

    Scans help doctors see how much inflammation you have, and where it is in your body.

  • Treating Crohn's Disease and Ulcerative Colitis

    There are many different treatments available to help you live well with Crohn’s or Colitis. Together with your IBD team, you can decide what treatment is right for you.


    You will probably have medicines called 5-ASAs (e.g. mesalazine, sulphasalazine) or steroids to reduce the gut inflammation. Steroids work quickly, but you can only take steroids for a short time.

    If you still feel unwell, you can take medicine to control your immune system. This stops your immune system attacking your gut.

    Your medicine can be given in different ways:

    Liquid diet

    Sometimes Crohn’s flare-ups can be treated with a liquid diet called enteral or parenteral nutrition. 


    Medicines help most people feel better, much of the time. But if medicine isn’t right for you, or you’re very unwell, surgery can also help.

    Surgery can remove the part of the bowel that’s making you feel unwell. If a lot of bowel is removed, you may need a stoma bag. Your bowel is brought outside your tummy, and your poo goes straight into the stoma bag.

    Having bowel surgery can be daunting, but many people find having a stoma is easier than feeling unwell with Crohn’s or Colitis.

    We have more information on Surgery for Crohn's Disease and Surgery for Ulcerative Colitis.

    My quality of life with a stoma is so much better than when I had a colon. I wish I had surgery before I did, because it has really improved my symptoms.

    Living with Ulcerative Colitis

  • Treating Microscopic Colitis
    Microscopic Colitis is often caused by medicines such as lansoprazole or NSAID painkillers. So if you stop taking these, you may feel better.

    Making changes to your diet and lifestyle may help. Common triggers are smoking, caffeine, and alcohol.

    People with Microscopic Colitis are also more likely to have coeliac disease. Ask your doctor to test if you have this. If you do, avoiding foods with gluten will help you feel better.


    Your doctor might give you tablets to stop your diarrhoea, or a steroid called budesonide.

    Be self-aware and find out everything you can. It’s easier if you can simply see it as part of you – and deal with it in a positive way.

    Living with Microscopic Colitis

  • Diet

    There’s no single diet that helps Crohn’s or Colitis. Keeping a food diary can help you find what works for you. Spicy and high fibre foods (like vegetables, nuts and wholegrains) make a lot of people feel worse when they’re in a flare-up - but everyone is different.

    The right diet also depends on how your Crohn’s or Colitis affects you. For example if you are low on iron, or have a stricture (narrowing) in the gut that makes it harder to digest food.

    It’s important to eat a healthy diet. Talk to your doctor or a qualified dietitian before making any big changes. 

  • Help and support from Crohn's & Colitis UK
    We offer information on many aspects of Crohn’s DiseaseUlcerative Colitis and other forms of Inflammatory Bowel Disease. You may be interested in our information on:

    Health professionals can order some publications in bulk by using our online ordering system. If you would like a printed copy of any of our information, please contact our helpline.

    Our helpline is a confidential service providing information and support to anyone affected by Crohn's or Colitis. Our team can:

    • Help you understand more about Crohn's or Colitis, diagnosis and treatment options
    • Provide information to help you to live well with your condition
    • Help you understand and access disability benefits
    • Be there to listen if you need someone to talk to
    • Help you to find support from others living with the condition

    Call us on 0300 222 5700


    Use our LiveChat 

    Crohn’s & Colitis UK forum

    This closed-group community on Facebook is for everyone affected by Crohn's or Colitis. You can share your experiences and receive support from others.

    Crohn’s & Colitis UK patient panels

    Patient panels, which are supported by Crohn’s & Colitis UK, are groups of people with Crohn's or Colitis who use their perspective as a patient to work with their IBD team to help improve their hospital services. For more information on patient panels, please contact our Patient Engagement Team.

    Crohn’s & Colitis UK Local Networks

    Our Local Networks of volunteers across the UK organise events and provide opportunities to get to know other people in an informal setting, as well as to get involved with educational, awareness-raising and fundraising activities. You may find just being with other people and realising that you are not alone can be reassuring. Families and relatives may also find it useful to meet other people with Crohn's or Colitis. All events are open to members of Crohn’s & Colitis UK.

  • 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 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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Helpline service


We know it can be difficult to live with, or support someone living with these conditions. But you’re not alone. We provide up-to-date, evidence-based information and can support you to live well with Crohn’s or Colitis.

Our helpline team can help by:

  • Providing information about Crohn’s and Colitis.

  • Listening and talking through your situation.

  • Helping you to find support from others in the Crohn’s and Colitis community.

  • Signposting you to specialist organisations.

Please be aware we’re not medically or legally trained. We cannot provide detailed financial or benefits advice or specialist emotional support.

Please contact us via telephone, email or LiveChat - 9am to 5pm, Monday to Friday (except English bank holidays).

Live chat

If you need specific medical advice about your condition, your GP or IBD team will be best placed to help.

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