What happens if ulcerative colitis is not treated?

Ulcerative colitis affects the lining of the large bowel. Active inflammation may lead to frequent diarrhoea, abdominal pain, urgency and blood in stool. Repeated bleeding can contribute to anaemia, while diarrhoea can cause dehydration and loss of nutrients. Ongoing symptoms may reduce appetite, disturb sleep and lead to unintentional weight loss. Severe inflammation can cause marked swelling of the bowel or a tear. Symptoms can fluctuate, but a quieter period does not prove that inflammation has gone.

Book a GP consultation if symptoms are new, persistent or returning. The clinician may review your history, examine your abdomen, arrange blood or stool tests and decide whether specialist assessment is needed. Keep taking prescribed medicine as directed unless your clinician advises otherwise, and record stool frequency, bleeding, pain, fever, food intake and fluid intake. Colorectal cancer screening or surveillance may be discussed as part of longer-term bowel care, depending on your history.

Get urgent help for heavy or repeated rectal bleeding, severe or worsening abdominal pain, a swollen abdomen, persistent vomiting, inability to drink, fainting, confusion, high fever or very frequent bloody diarrhoea. These features can indicate severe inflammation, dehydration, significant blood loss or a bowel complication.

Ask how active the inflammation appears to be, which tests are needed, how to manage a flare, which medicines require monitoring, and what bleeding or pain should prompt emergency assessment.