Blood in stool and vomiting: what to know

The appearance matters. Bright red blood may come from the lower bowel or anal area, while very dark, tar-like stool can indicate digested blood higher in the digestive tract. Vomiting may occur with gastroenteritis or food poisoning, and abdominal inflammation from pancreatitis or gallstones can also cause marked illness. Migraine can cause vomiting, but it does not explain blood in stool; a separate source still needs consideration.

In children, rotavirus infection can cause vomiting and diarrhoea, but blood is not something to dismiss. Meningitis can cause severe illness and vomiting with other warning signs, so the overall picture matters more than one symptom.

Contact a healthcare professional promptly and describe the blood colour, amount, stool appearance, vomiting frequency, abdominal pain, fever, and ability to keep fluids down. Take small sips of oral fluid if you can, but do not force food. Avoid anti-diarrhoeal or pain medicines unless a clinician advises them, and do not wait for the symptom to recur before seeking guidance.

Get emergency help for heavy or ongoing bleeding, black tar-like stool, vomit that contains blood or looks like coffee grounds, severe or worsening abdominal pain, a swollen abdomen, faintness, confusion, or breathing difficulty. Urgent care is also needed when repeated vomiting prevents fluids, urine becomes very infrequent, or there is unusual sleepiness, especially in a child or older adult.

Ask where the bleeding may be coming from, whether you need examination or blood and stool tests, and how to replace fluids safely. Ask which medicines to avoid and what changes should prompt an immediate return to emergency care.