What should you know about old blood in vomit?

Blood changes colour and texture when it stays in contact with stomach acid. Vomit that looks brown, blackish or grainy may therefore contain older blood rather than fresh bright-red blood. Causes can include irritation or an ulcer in the stomach or upper intestine, a tear after forceful vomiting, liver-related bleeding, medicines that affect clotting, or a problem in the oesophagus or stomach. Cancer is one possible cause, but this symptom alone cannot identify the cause.

The amount of bleeding is not reliably judged by appearance. Light-headedness, weakness, pale or clammy skin and black stools can indicate blood loss. A clinician may check your circulation and blood count and may arrange tests to find and treat the source.

Treat vomiting blood as a medical concern even if the material looks old or the vomiting has stopped. Contact an urgent medical service now for advice and avoid driving if you feel faint or weak. Do not take aspirin, ibuprofen or another medicine that can worsen bleeding unless a clinician specifically tells you to do so. Note the colour and amount, recent medicines, alcohol use, abdominal pain and black stools so you can describe them clearly.

Call emergency services for fainting, confusion, severe weakness, rapid or shallow breathing, cold clammy skin, severe abdominal or chest pain, repeated vomiting of blood, or black stools with dizziness. Urgent assessment is also needed if you take a blood thinner, have known liver disease, or cannot keep fluids down. Do not wait for the symptom to recur before seeking help.

Where might the bleeding be coming from? Could any of my medicines contribute? Do I need blood tests or an examination of the upper digestive tract? What should I do with prescribed blood thinners or pain medicines? Which changes after discharge should prompt an immediate return?