Stomach cramps, diarrhoea, nausea and blood in stool

An inflamed or infected bowel can cause cramps, loose stools, nausea and visible blood. Gastroenteritis is one possible explanation, while Crohn's disease and ulcerative colitis can cause repeated inflammation and bleeding. Diverticular disease, a tear near the anus, or another source in the digestive tract can also bleed. The appearance matters: bright red blood may be seen near the end of the bowel, while black, tar-like stool can indicate bleeding higher up. Bowel cancer, rectal cancer, or a gastrointestinal stromal tumour are less common possibilities but should not be dismissed when bleeding persists, recurs, or occurs with weight loss or a change in bowel habit.

Contact a clinician promptly and describe the colour and amount of blood, how often it appears, and whether it is mixed through the stool or only on the paper. Note pain, vomiting, fever, dizziness, recent travel, sick contacts, medicines such as anti-inflammatories or blood thinners, and any previous bowel condition. Sip fluids if you can keep them down and choose light foods. Do not take leftover antibiotics or anti-diarrhoeal medicines without advice when blood is present. A clinician may decide that an examination, blood tests, stool tests, or a camera examination of the bowel is appropriate.

Go to urgent care for a large amount of blood, black tarry stool, fainting, confusion, severe weakness, a fast heartbeat, severe or worsening abdominal pain, a swollen or rigid abdomen, repeated vomiting, or inability to drink. Seek same-day advice if bleeding continues, diarrhoea is frequent, fever develops, or you feel dehydrated. Prompt assessment is also important if you take blood-thinning medicine, have a known bowel disease, or the bleeding is unexplained and recurring.

Where might the bleeding be coming from? Do my medicines or bowel history change the urgency? What tests could explain the bleeding, and what should I do if it happens again?