Vomiting blood (haematemesis) could be a sign of a serious problem .

You should go to your GP surgery or nearest A&E department.

The amount and colour of blood can vary. For example:

• you may have vomited large amounts of bright red blood
• there may be streaks of blood in your vomit, mixed with food
• there may be what look like coffee grounds in your vomit, which means the blood has been in your stomach for a few hours

Keep a small sample of the vomit to show a GP or the doctor treating you. It will give them a better idea of what's wrong.

What to expect when you see a doctor

Unless you're generally well and the cause is obvious to a doctor – for example, you have swallowed blood from a nosebleed – you should be admitted to hospital straight away for tests.

These will include blood tests and an endoscopy. An endoscopy is where a long, thin, flexible tube that has a light and camera at one end is used to look inside your digestive tract.

It's important to confirm whether the blood you've vomited has come from your stomach or food pipe (oesophagus) or if you have coughed it up from your airways or lungs.

Find out more about coughing up blood.

Common causes of vomiting blood

If you vomit blood, it means there may be bleeding somewhere in your food pipe, stomach or the first part of your small intestine (duodenum).

This is a summary of the most likely causes of blood in vomit. Do not use this list to diagnose yourself – always see a GP or go to A&E.

Stomach ulcer or severe gastritis

If you vomit blood and also have a burning or gnawing pain in your tummy (stomach), the most likely causes are a stomach ulcer or severe inflammation of the stomach lining (gastritis).

Bleeding happens when the ulcer or inflammation damages an artery.

Oesophageal varices

Oesophageal varices are enlarged veins in the lower part of the food pipe (oesophagus). They bleed, but do not usually cause any pain.

They're often caused by alcoholic-related liver disease. If a GP or A&E doctor suspects oesophageal varices are the cause of blood in your vomit, you'll need to be admitted to hospital immediately.

Severe gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GORD) is where acid leaks out of the stomach and up into your food pipe (oesophagus).

If you have severe GORD, the acid can irritate the lining of your oesophagus and cause bleeding.

Tear in the food pipe (oesophagus)

Prolonged retching can tear the lining of your oesophagus, which can also result in bleeding.

Swallowed blood

It's possible to swallow blood in certain circumstances – for example, after a severe nosebleed.

These conditions may also cause you to have blood in your poo, which can make it look black and like tar.

Less common causes of vomiting blood

Less commonly, blood in your vomit may be caused by:

• swallowing a poison – such as corrosive acid or arsenic
• a blood condition – such as a reduced number of platelets in the blood (thrombocytopenia), leukaemia, haemophilia or anaemia
• oesophageal cancer or stomach cancer – these types of cancer are uncommon, but they may be suspected if you're over 55 and you've also lost a lot of weight