Lung cancer and vomiting blood: what to do

Blood in vomit may look bright red, dark brown, or like coffee grounds. It can come from the oesophagus or stomach, including irritation, an ulcer, medication effects, or another condition. Blood coughed up from the airways can be mistaken for vomit, especially after swallowing it. The difference is not always clear at home.

Lung cancer and its treatments can affect bleeding risk, appetite, swallowing, or the medicines a person takes, but vomiting blood is not explained by lung cancer alone. [Oesophageal Cancer](/conditions/oesophageal-cancer/) and [Stomach Cancer](/conditions/stomach-cancer/) are examples of digestive conditions clinicians may consider, alongside more common causes.

Seek emergency medical help immediately. Do not drive if the person is weak, dizzy, faint, confused, or actively bleeding. Keep them sitting upright or on their side if drowsy, and do not give food, drink, or extra medicine unless emergency clinicians advise it. Bring a list of medicines, especially blood thinners or anti-inflammatory medicines, and note the colour and amount of blood.

Tell clinicians whether the blood was vomited or coughed up, whether black stools or abdominal pain are present, and whether there has been recent chemotherapy, radiotherapy, surgery, or severe retching.

Emergency help is essential for any vomiting of blood, and especially for repeated bleeding, a large amount, fainting, rapid breathing, pale or clammy skin, severe abdominal or chest pain, confusion, or black stools. Do not wait to see whether the symptom settles. If the person is receiving cancer treatment, inform the oncology team after emergency help has been arranged.

Ask where the bleeding is thought to have started, which medicines should be paused or continued, what tests are needed, and how to reduce the chance of recurrence. Ask how the bleeding affects the cancer treatment plan and which symptoms should trigger another emergency call.