Gastrointestinal bleeding (also referred to as GI bleeding) is a problem that you can’t ignore. It can be a sign of something as simple as haemorrhoids or as serious as cancer.It’s important to discuss any concerns you have about GI bleeding with your doctor so that they can investigate further. However, if you have a large or new GI bleed it’s important to seek medical review urgently, as it can be an emergency. GI bleeding isn’t always as obvious as it may seem. It can come in many forms:Vomiting fresh or red bloodVomiting dark or digested blood. People often describe this as vomit which looks like coffee groundsFresh blood on wiping after using the toiletFresh blood mixed with stoolsDark or black stoolsThere may be more subtle signs of GI bleeding too, such as fatigue, breathlessness and weight loss. Some of these more subtle signs are due to anaemia or low iron, stemming from blood loss. This is more common when you have been losing small amounts of blood over a long period of time, often without realising it.If you have any signs of GI bleeding your doctor will ask you questions to find out exactly what is happening before doing a thorough examination. They may also run some blood tests or ask for you to get a stool sample to detect signs of bleeding.Some causes of GI bleeding such as haemorrhoids can be diagnosed and treated by your general practitioner. Others will involve being referred to a gastroenterologist, who is a doctor who specialises in problems to do with your gastrointestinal system.If you’re referred to a gastroenterologist they may suggest an endoscopy to further investigate the location and cause of the bleeding. This is where a tube with a light and a small camera is used to get pictures inside of your body. Depending on your symptoms you may have a gastroscopy or a colonoscopy. Gastroscopy involves using the small tube to look at your oesophagus (the pipe running from your mouth to your stomach) and your stomach. This may be used if you’ve been vomiting blood or if your gastroenterologist thinks it’s likely the bleeding is in this area based on your other symptoms. Colonoscopy involves looking inside your rectum and large bowel. This can identify sources of bleeding in the last parts of your gastrointestinal system, so may be used if you’re passing fresh blood in your stools or have other symptoms such as constipation.Once you’ve been investigated by a gastroenterologist the cause of your bleeding will likely have been identified. Causes include:Mallory-Weiss tears, which are small tears in your oesophagusUnusually large or exposed blood vesselsUlcers in your stomach or the upper part of your small intestineCancerous tumours in your stomach or bowelInflammatory bowel disease, such as ulcerative colitis or Crohn’s diseaseHaemorrhoids or anal fissuresTreatments vary depending on the cause. If you’ve lost a lot of blood, either in a short period or over a long time, you may need additional iron or even a blood transfusion. Your doctor will be able to advise you on what is needed and answer any questions you may have.