Ulcerative colitis

Ulcerative colitis is a long-term condition where your large bowel (colon and rectum) gets swollen and inflamed.

Your colon is your large intestine (bowel). Your rectum is the end of your bowel, where poo is stored.

If you have ulcerative colitis, you get swelling, inflammation and ulcers in the lining of your large bowel. They can bleed and produce pus.

Ulcerative colitis can affect people of all ages, but it’s usually diagnosed between the age of 15 and 40.


The main symptoms of ulcerative colitis are:

You may also experience:

  • extreme tiredness (fatigue)
  • loss of appetite
  • weight loss

Some people also get symptoms in other parts of their body. For example, some people develop:

  • painful and swollen joints (arthritis)
  • mouth ulcers
  • areas of painful, red and swollen skin
  • irritated and red eyes

Non-urgent advice: Speak to your GP practice if:

  • you have symptoms of ulcerative colitis and you haven't been diagnosed with the condition

Symptoms of a flare-up

Some people may go for weeks or months with very mild symptoms, or none at all. This is known as remission. This may be followed by periods where the symptoms are particularly troublesome. These are known as flare-ups or relapses.

Symptoms of flare-ups vary from person-to-person. They may include:

  • diarrhoea 6 or more times a day
  • blood or mucus in your poo
  • severe abdominal pain
  • symptoms in other parts of your body

Severe ulcerative colitis can also cause symptoms like:

  • shortness of breath
  • a fast or irregular heartbeat
  • a high temperature (fever)
  • blood in your poo becoming more obvious

Non-urgent advice: Speak to your inflammatory bowel disease (IBD) team if:

  • you have ulcerative colitis and think you're having a flare-up


The exact cause of ulcerative colitis is unknown.

A combination of factors may be responsible, including:

  • problems with your immune system – where the immune system mistakenly attacks the lining of your large bowel, making it inflamed
  • genetics – genes you inherit from your family
  • environmental factors – like air pollution, medication and viruses or bacteria in your gut


To help diagnose ulcerative colitis, your GP will ask about your:

  • your pattern of symptoms
  • your diet
  • any recent travel – for example, you may have developed travellers' diarrhoea
  • whether you're taking any medication, including any over-the-counter medicines
  • whether anyone else in your family has a bowel condition
  • any health problems you’ve had in the past

Your GP may also:

  • examine your abdomen (tummy)
  • ask for a stool (poo) sample and use a qFIT test to check for blood and mucus, infection or inflammation via a faecal calprotectin test
  • arrange blood tests to check for inflammation or anaemia

Additional tests for ulcerative colitis

If your GP thinks that you have ulcerative colitis you may be referred to hospital for more tests. These could include:

  • colonoscopy – a thin, flexible tube with a camera is put into your bottom to look at the whole of your large bowel
  • sigmoidoscopy – a thin, flexible tube with a camera is put into your bottom to look at the end of your large bowel
  • X-ray
  • MRI scan or computerised tomography (CT)

You will be told what tests you need and what you need to do to prepare for them.


Treatment for ulcerative colitis aims to relieve and prevent symptoms.

Your treatment will depend on how severe your symptoms are and how often they flare up. Mild flare-ups can be usually be treated at home. But severe flare-ups usually need treatment in hospital to reduce the risk of complications.

Treatment will usually be provided by a range of healthcare professionals.


Most people will get medication to treat symptoms of ulcerative colitis. This includes medications like:

  • aminosalicylates (ASAs) – often the first treatment option, used to get and keep inflammation under control and can be given rectally as well as orally
  • corticosteroids – used to get inflammation under control quickly, but not suitable for long-term use

If you have lots of flare-ups or aminosalicylates do not keep your inflammation under control, you may need other treatments, such as:

  • immunosuppressants like azathioprine or mercaptopurine – used to reduce the activity of the immune system
  • biologic medicines, like adalimumab, infliximab, golimumab, ustekinumab or vedolizumab
  • other advanced medicines like filgotinib, ozanimod, tofacitinib and upadacitinib


Surgery to treat ulcerative colitis may be an option if:

  • you choose to have surgery instead of taking medications that may cause side effects
  • medications don't control your symptoms
  • your quality of life is severely affected by your condition
  • you have serious complications of ulcerative colitis

Surgery for ulcerative colitis involves removing part or all of your large bowel (known as a colectomy). This means the small intestine must be used to pass waste products out of your body instead.

During the surgery, your small intestine will either be:

  • joined to the surface of your tummy (known as an ileostomy or a colostomy) – after this type of surgery, poo comes out of the opening on your tummy and is collected in special bags that you wear
  • joined directly to your rectum (the end of your large bowel), so your poo comes out of your bottom as usual
  • used to create an internal pouch that's connected to your bottom (known as an ileo-anal pouch or J-pouch) – this means your poo can pass through your bottom as usual


There’s no evidence that a particular diet causes ulcerative colitis. But alongside medications, some changes to your diet may help control symptoms for some people.

You could:

  • eat 5 to 6 small meals rather than 3 main meals
  • try to eat a healthy, varied diet that includes a wide variety of fruit, vegetables, nuts, seeds, proteins and wholegrains
  • drink plenty of water

You could also speak to your IBD team about:

  • keeping a food diary to find out if any particular foods affect your symptoms
  • removing trigger foods from your diet – but do not make major changes to your diet without talking to your IBD team and make sure you are still getting all the nutrients you need
  • taking a food supplement if you are struggling to get enough nutrients from your diet
  • being referred to a dietitian

Managing stress

Stress doesn't cause ulcerative colitis. But, managing stress may reduce how often you get symptoms.

To help manage stress, you could:

  • exercise – speak to your IBD team about a suitable exercise plan
  • try relaxation techniques like yoga, medication and breathing exercises
  • talk to others – Crohn's & Colitis UK has details of local support groups
  • speak to your GP if you think you may have depression

Fertility and pregnancy

A woman's chance of becoming pregnant isn't usually affected by ulcerative colitis.

However, surgery for ulcerative colitis might affect your fertility, especially pouch surgery.

Most women with ulcerative colitis will have a normal pregnancy and a healthy baby. But if you're pregnant or planning a pregnancy you should discuss it with your IBD team. This is because they may need to change your medication.

If you're having a flare-up of ulcerative colitis you may also be advised to avoid getting pregnant until it's under control.


If you have ulcerative colitis, you may be at an increased risk of developing other problems. This can include:

  • osteoporosis
  • poor growth and development in children and young people

More serious and rare complications can include:

  • primary sclerosing cholangitis (PSC) – inflammation in the bile ducts, which can lead to liver damage
  • narrowing’s in the bowel (strictures) that may become blocked or make it difficult for poo to pass through
  • toxic megacolon – severe inflammation in the colon may lead to trapped gas so the colon becomes very enlarged and can rupture
  • a higher risk of getting bowel cancer
  • a higher risk of getting blood clots in your legs or lungs

Last updated:
24 March 2023