What should you know about fainting and vomiting blood?

Fainting with vomiting blood is an emergency warning sign that needs immediate medical assessment, especially if weakness or confusion continues. Blood may look bright red, dark brown, or like coffee grounds. Fainting can occur when circulation to the brain falls, including during blood loss, dehydration, or a sudden drop in blood pressure.

Vomiting blood usually comes from bleeding in the upper digestive tract, such as the oesophagus, stomach, or first part of the small intestine. Possible causes include an ulcer, irritation or a tear after forceful vomiting, liver-related vein changes, medicines that affect clotting, or a tumour. The symptom does not establish cancer; oesophageal and stomach cancers are among the conditions clinicians may need to assess.

Black stools, abdominal pain, rapid breathing, clammy skin, thirst, or reduced alertness can accompany a significant bleed. The amount seen in vomit can underestimate the total loss, so feeling better briefly does not make the event safe to ignore.

Call emergency services or go to an emergency department now. Do not drive yourself. Lie on your side if vomiting or drowsy, and have someone stay with you. Avoid food, alcohol, and medicines such as aspirin or ibuprofen unless an emergency clinician tells you otherwise. Bring a list of medicines and describe the colour and amount of blood as accurately as possible.

Emergency help is needed for any fainting episode with blood in vomit, repeated vomiting, ongoing dizziness, confusion, severe pain, pale or clammy skin, fast breathing, or black stools. Do not wait for a routine appointment, even if the bleeding stops. A clinician may need blood tests, monitoring, fluids, and a procedure to locate or control the bleed.

Where is the bleeding likely to be coming from? Could any medicine or medical condition have contributed? Do I need an endoscopy or other tests? What warning signs should bring me back immediately?