Does ulcerative colitis cause diarrhoea?

Inflammation in the colon can make the bowel move contents more quickly and reduce its ability to absorb water. This can lead to loose stools, urgency, mucus, cramps, or waking at night to use the toilet. Some people also notice blood or a sensation of incomplete emptying. Infections, medicines, food-related problems, and other bowel disorders can cause similar symptoms, so a clinician may need to distinguish a flare from another cause.

Replace fluid and salts with frequent drinks; oral rehydration solution may help when losses are ongoing. Choose foods you tolerate and record stool changes, urgency, pain, bleeding, fever, and recent antibiotics or travel. Contact your healthcare team if diarrhoea is new, persistent, or different from your usual pattern. Follow your prescribed plan and check before using anti-diarrhoea medicine, particularly if you have fever or blood in the stool.

Seek urgent medical attention for severe dehydration, fainting, confusion, very little urine, repeated vomiting, severe abdominal pain, a swollen abdomen, or heavy bleeding. Fever with rapidly worsening diarrhoea or marked weakness also needs prompt review. These symptoms may reflect serious inflammation, infection, or fluid loss.

Ask whether this could be a flare or infection, whether testing is needed, how much fluid to take, and which symptoms mean your treatment plan should change.