Blood in diarrhoea and vomit: what to do

Food poisoning and gastroenteritis can inflame the stomach or bowel and cause blood, cramps, fever, diarrhoea and vomiting. Repeated retching can irritate the throat or upper digestive tract, leaving bright streaks in vomit. Dark, coffee-ground-like vomit or black, tarry stool may indicate digested blood. Severe upper-abdominal pain can occur with pancreatitis or gallstones, while other symptoms may point to a different illness. The colour, amount, pain and timing help a clinician decide how urgently you need examination.

Seek medical advice promptly rather than treating the bleeding at home. Until assessed, take small frequent sips of oral fluids if you can swallow and keep a record of vomiting, stool colour, urine output, fever and pain. Avoid alcohol and anti-inflammatory painkillers unless a clinician has told you to use them. Do not prepare food for others while infectious vomiting or diarrhoea is possible, and wash hands carefully.

Go to emergency care for heavy or repeated blood, black stool, coffee-ground vomit, severe or worsening abdominal pain, a rigid abdomen, faintness, confusion, very little urine, or inability to keep fluids down. Urgent help is also needed with stiff neck, severe headache, a widespread rash, or marked weakness. Children, older adults, pregnant people and anyone with significant medical conditions can become dehydrated quickly.

Ask whether you need tests for infection, dehydration or bleeding, which fluids and medicines are suitable, and what symptoms require emergency reassessment. Report recent meals, travel, sick contacts, medicines and the first time you saw blood.