Ulcerative colitis

Expert reviewer, Dr Ian Arnott, Consultant Gastroenterologist
Next review due December 2021

Ulcerative colitis is a condition that affects your large bowel and rectum (back passage). The lining of these becomes inflamed and ulcers can develop. This can give you bloody diarrhoea, which may come and go.

Ulcerative colitis is a life-long condition but there are lots of treatment options to help control it and prevent your symptoms from happening.

An image showing a diagram of the large and small bowels

About ulcerative colitis

Ulcerative colitis is one of the two major types of inflammatory bowel disease (IBD) – the other is Crohn’s disease. See our FAQs for the differences between these two conditions. In ulcerative colitis, the lining of the gut becomes inflamed and swollen and ulcers develop. The affected areas may bleed and produce mucus, which you then pass out when you go to the toilet.

Around 146,000 people in the UK have ulcerative colitis. Most people develop it between the ages of 15 and 25 or when they’re older – between 55 and 65. But you can get ulcerative colitis at any time in your life.

You’ll usually have ulcerative colitis for the rest of your life but your symptoms might follow what’s called a ‘relapsing and remitting’ pattern. This means your symptoms can disappear – sometimes for months or even years – and then flare up again from time to time. Many people have flare-ups at least once a year.

Describing ulcerative colitis

If you have ulcerative colitis, you may hear different terms used to describe your condition. These tend to depend on how much of your large bowel is involved and how severely you’re affected.

How much large bowel is affected

Ulcerative colitis usually affects the lowest part of your bowel (your rectum). However, it can spread to affect some or all of the rest of your large bowel too. You may hear the following terms mentioned when describing different types of ulcerative colitis.

  • Proctitis – ulcerative colitis that only affects your rectum.
  • Proctosigmoiditis – inflammation in your rectum and sigmoid colon (the part of your large bowel closest to your rectum).
  • Left-sided colitis – inflammation that begins in your rectum and continues into the left side of your large bowel.
  • Extensive colitis – ulcerative colitis that affects most or all of your large bowel (also called pancolitis).


During a flare-up, your doctor may describe your ulcerative colitis as one of the following.

  • Mild – you pass faeces (stools) fewer than four times a day, with no more than small amounts of blood. You don’t feel generally unwell.
  • Moderate – you pass faeces four to six times a day, with some blood in it, but you don’t feel unwell.
  • Severe – you pass faeces six or more times a day and you feel unwell. Your temperature and heart rate may be raised and you may have anaemia.
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Symptoms of ulcerative colitis

The symptoms of ulcerative colitis usually come and go. You may have periods without any symptoms (these are known as remission) and periods when you do have symptoms (these are known as flare-ups). You may find that you feel perfectly well between flare-ups, with no symptoms at all.

During a flare-up, the main symptom is diarrhoea which may have blood or mucus in it. You may have lower abdominal (tummy) pain or cramps and need to rush to the toilet, even at night. The pain may then go away after you’ve been. You might feel you need to empty your bowels even though there’s nothing to pass – doctors call this ‘tenesmus’.

Other symptoms include:

  • feeling extremely tired
  • losing weight
  • feeling generally unwell
  • losing your appetite
  • having a raised temperature

If you have ulcerative colitis, you may develop anaemia from the disease itself or from losing a lot of blood through your bowel movements. This can make you feel very tired. There are treatments for anaemia.

There’s a chance that you could develop problems in other parts of your body too. For example, you might get mouth ulcers, skin rashes and inflammation (redness or pain) in your eyes, skin or joints. These problems can occur during a flare-up or while you’re in remission.

If you have any of these symptoms, contact your GP for advice.

Diagnosis of ulcerative colitis

Your GP will ask about your symptoms and examine you. They’ll also ask about your medical history and if any of your family has bowel problems. Your GP will ask if you’ve travelled abroad recently to check if you might have an infection. They may ask you for a sample of faeces, which is called a stool sample. This will help to rule out a bacterial infection. They’ll ask you to have a blood test too.

Depending on the results, your GP may refer you to a gastroenterologist. This is a doctor who specialises in conditions that affect the digestive system.

You might need to have more tests, which can include the following.

  • Faecal calprotectin. This will allow your doctor to rule out other conditions, such as irritable bowel syndrome. You’ll be asked to provide another sample of faeces for this test.
  • Colonoscopy. In this test, your doctor will look at the lining of your large bowel to check for any ulcers or inflammation.
  • Flexible sigmoidoscopy. In this test, your doctor will look inside your rectum and the lower part of your bowel.
  • Biopsy. Your doctor may take a small sample of the tissue (a biopsy) from inside your bowel during a colonoscopy or sigmoidoscopy. This will be tested in a laboratory to look for the tissue changes seen in ulcerative colitis.
  • X-ray of the abdomen. This is usually only done in the case of a severe flare-up. It may help to rule out serious problems like toxic megacolon (see our section ‘Complications of ulcerative colitis’).
  • CT scan or an MRI scan. These will help to show how much of your large bowel is affected by ulcerative colitis.

Treatment of ulcerative colitis

There isn’t a cure for ulcerative colitis but there are treatments that can help to settle flare-ups and keep your symptoms away for longer. When your symptoms disappear for a time, this is called remission.

The treatment you have will depend on how severe your ulcerative colitis is, how it responds to treatment and how much of your large bowel is affected. Your own preferences will also be taken into account. You will be cared for by a team of healthcare professionals with specialist knowledge of inflammatory bowel diseases (your IBD team).


Medicines can control your symptoms and prevent flare-ups. You may need to take different medicines when you’re in remission and when you’re having a flare-up. It’s really important to keep taking your medicines as your doctor recommends, even if you’re feeling well.

Medicines for ulcerative colitis include the following.

  • Aminosalicylates, such as mesalazine. You can take these as tablets to swallow or as a suppository (a dissolvable capsule you insert into your rectum) or enema (where liquid is pumped into your rectum). Often you may have both. You can take aminosalicylates during flare-ups and also between flare-ups to keep your symptoms away for longer.
  • Steroids (also called corticosteroids), such as prednisolone. You may need to take these if aminosalicylates don’t control your symptoms when you’re having a flare-up. You can take steroids as tablets, some of which are designed to release the medicine once the tablet reaches your colon. This may help to reduce side-effects. Alternatively, you can take steroids as a rectal suppository or enema. You may also be given steroids through a drip if your flare-up is very severe (see ‘Treating severe flare-ups’).
  • Immunosuppressants (to suppress your immune system), such as azathioprine. Your doctor may prescribe these if your symptoms haven’t improved with other treatments or after a severe flare-up.
  • Monoclonal antibodies, such as infliximab. Your doctor may suggest you take a monoclonal antibody if other treatments haven’t worked for you.

It is important that you know the possible side-effects of any medicine that you take and weigh this against the benefits. If you have any questions you should talk these over with your IBD team before starting treatment. If you have any questions about taking your medicines, ask your pharmacist or doctor.

Treating severe flare-ups

If you have a severe flare-up of ulcerative colitis you may need to go into hospital urgently. This is because you’ll need specialist care and intravenous medicines (medicines given directly into your vein). Your doctor will probably offer you intravenous steroids. If these don’t work well or aren’t suitable for you, your doctor may recommend you have a medicine called ciclosporin or monoclonal antibodies such as infliximab. For a few people, urgent surgery to remove the bowel may be necessary.


Sometimes, an operation to remove the large bowel (a colectomy) is needed as an emergency treatment for a severe flare-up. But usually, surgery for ulcerative colitis is something which is planned in advance.

Surgery may be an option if medicines don't help to improve your symptoms. Or you may think about having surgery if you’re getting lots of flare-ups that seriously affect your quality of life. If you’re considering having surgery, it’s important that you discuss all the pros and cons with your doctor first. Around one in three people who have ulcerative colitis eventually have surgery.

When your large bowel is removed, your small bowel will be redirected so that your body is still able to get rid of waste products. You’ll probably need to have a temporary or permanent ileostomy. This is where your surgeon brings your small bowel out to open on the surface of your abdomen. An ileostomy bag, attached over the opening, collects waste.

Your doctor will talk to you about what kind of operation is best for you and what’s involved. The most common types of surgery for ulcerative colitis are briefly described here.

  • Pouch surgery (also called ileal pouch-anal anastomosis, IPAA surgery). Your surgeon will remove your large bowel and rectum. They’ll then make a pouch from the end of your small bowel, and stitch this to your anus. This means your bowel movements can pass through your anus. You may need a temporary ileostomy for a few months so that waste can be diverted while the new pouch heals. Your surgeon will then close the ileostomy.
  • Subtotal colectomy with ileostomy. Your surgeon will remove most of your large bowel but leave your rectum. You’ll need to have an ileostomy but this may not be permanent – later on you may be able to have pouch surgery.
  • Proctocolectomy with permanent ileostomy. Your surgeon will remove all of your large bowel, rectum and anus, and close off your back passage. You’ll need a permanent ileostomy.

You can find out more about the types of surgery and what they involve by visiting the website of Crohn’s & Colitis UK. See also our section ‘Other helpful websites’.

Causes of ulcerative colitis

Doctors don’t yet know exactly why people develop ulcerative colitis. We know it runs in families – if you have a close family member with ulcerative colitis, you’re about 10 times more likely to develop it. Your chance of getting ulcerative colitis may also be affected by your environment and some parts of the Western lifestyle such as our diet.

One theory is that, in some people, ulcerative colitis develops when the immune system overreacts to the ‘friendly’ bacteria in your bowel. But no one is sure. It’s likely that a combination of things are involved.

Complications of ulcerative colitis

Ulcerative colitis can lead to a number of complications.

  • Toxic megacolon. This is when your inflamed large bowel becomes dilated (enlarged) as part of a severe flare-up. You’ll probably feel very unwell with a high temperature, fast heart rate and abdominal pain. It’s uncommon – but if you get these symptoms, seek urgent medical attention. You might need an operation to treat it.
  • Bowel cancer. Ulcerative colitis can slightly increase your risk of getting bowel cancer. This risk is higher if you’ve had ulcerative colitis for a long time, if it’s not well-controlled and if a lot of your bowel is affected. You’ll need to have regular colonoscopies to check for any signs of cancer. These should start about 10 years after you first get symptoms. Keeping your colitis under control may help to reduce your risk of bowel cancer.
  • Primary sclerosing cholangitis. In this complication of ulcerative colitis, your bile ducts become more and more inflamed and damaged over time. Bile ducts are tubes that connect your liver and gallbladder to your small bowel.

Living with ulcerative colitis

Ulcerative colitis is a life-long condition that can affect you physically and emotionally. Being unpredictable, flare-ups can have a big impact on your social life, education or work. However, many people with ulcerative colitis manage to live life to the full.

It’s natural that the challenges of living with ulcerative colitis make you feel stressed at times. This can trigger flare-ups so you may want to try some techniques to help you relax. One you might find helpful is mindfulness – see our information on mindfulness to learn more.

Regular exercise will help to relieve tiredness and it can also improve your general health and help to keep your bones strong. This is important because some medicines for ulcerative colitis may make you more likely to develop osteoporosis. See our information on how to get started with exercise.

Planning trips out

Having ulcerative colitis might mean you feel anxious about going out, so it may be a good idea to plan ahead.

  • Before going out, find out where the nearest public toilets are. Some people carry a card saying they need to use the toilet urgently, for use in places such as shops and pubs.
  • If you’re worried about having an accident, carry spare clothing in your bag so you can change. You may also want to carry moist wipes, and plastic bags for soiled clothes.

Being prepared for a flare-up

Flare-ups can be unpredictable. To help you be prepared, make a flare-up plan.

  • Talk to your doctor and nurse about what to do when you have a flare-up. You may need to adjust the medicines you take.
  • If you’re able to take them, carry a supply of steroid tablets with you when you travel on holiday. If you have a flare-up, you’ll be able to treat it straight away.

Getting support

Telling your family and friends about your condition and how it affects you, may help them support you. You’ll also be supported by your IBD team. If you feel that you need more support, you could attend a self-help group to talk things through. Internet blogs and online chat forums and message boards can also be a huge source of support.

You’ll find a lot of information from other patients and discussion forums online, but remember that not everything you read will be helpful. For organisations that can offer well-informed advice, see our section ‘Other helpful websites’. Crohn’s & Colitis UK has lots of information, tips and hints to help make life easier for you if you have ulcerative colitis.

Ulcerative colitis and pregnancy

Most women with ulcerative colitis have a normal pregnancy and a healthy baby; being pregnant doesn’t usually affect your symptoms. If possible, it’s best to get your symptoms under control before becoming pregnant. A flare-up while you’re pregnant makes it more likely that you’ll give birth early or your baby will have a low birth weight. If you’re thinking of starting a family, talk to your doctor so that they can give you the right advice and support.

Frequently asked questions

  • There’s been a lot of research into whether certain types of food can cause ulcerative colitis. At the moment, it’s still not clear. Some experts think that ulcerative colitis is linked to a diet that is high in fats and sugar, and low in fruit and vegetables.

    There isn’t a specific diet which is recommended for ulcerative colitis. However, you may find that some food can make your symptoms worse. Foods that might affect your symptoms include:

    • foods that are high in fibre
    • foods that produce gas (for example, beans or cabbage)
    • spicy foods
    • dairy products (for example, milk, cream and cheese)
    • drinks with alcohol or caffeine

    You can keep a food diary to record what you eat and how severe your symptoms are. This will help you to see if any types of food make your symptoms worse. Consider avoiding them, but don’t forget it’s very important to still eat a healthy balanced diet. You can try introducing these foods again when your flare-up settles down. Don't cut any entire food groups from your diet altogether without talking to your doctor or dietitian first.

    Diarrhoea can cause dehydration so make sure you drink enough fluid to prevent this.

    If you have an ileostomy, there’s no need to follow a special diet unless you’re advised to do so by your doctor.

  • You often find ulcerative colitis and another condition called Crohn’s disease put together under the heading ‘inflammatory bowel disease’. They’re both long-term conditions which cause episodes of inflammation of your digestive system. Symptoms of both can include diarrhoea with blood and mucus in it, abdominal cramps and losing weight.

    One of the main differences between Crohn’s disease and ulcerative colitis is in which parts of the digestive system they affect. Crohn's disease affects any part of your digestive system from your mouth to your anus whereas ulcerative colitis only affects your large bowel and rectum. Unlike ulcerative colitis, Crohn’s disease can be patchy – affecting some areas with other, unaffected areas between.

    Treatment with medicines is similar for both conditions. If you have ulcerative colitis and medicines aren’t helping, you may be able to have an operation to remove your large bowel. If you have Crohn's disease, surgery won’t cure your condition but may help your symptoms.

    Sometimes, doctors can find it hard to tell if a person has Crohn’s disease or ulcerative colitis – it isn’t always clear cut.

    For more details, see our information on Crohn’s disease.

  • If you have ulcerative colitis, you have a slightly increased risk of developing bowel cancer. Your risk is greater if a large portion of your bowel is affected or you’ve had severe ulcerative colitis for a long time.

    Your risk of getting bowel cancer seems to be lower if you regularly take aminosalicylates, such as mesalazine. And it’s important to keep your ulcerative colitis symptoms well controlled.

    Lifestyle changes, such as doing some regular exercise, stopping smoking and eating a healthy diet may also reduce your risk of bowel cancer. For more on this, see our information on bowel cancer.

    It’s also important to monitor your condition so that any signs of cancer can be spotted early. Your doctor may advise you to have regular colonoscopies to check your bowel for early signs of cancer. They’ll let you know how often you need these. It will depend on how long you’ve had ulcerative colitis, how much bowel is involved and how severe your symptoms are.

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  • Reviewed by Dr Kristina Routh, Freelance Health Editor, December 2018
    Expert reviewer, Dr Ian Arnott, Consultant Gastroenterologist
    Next review due December 2021