This can happen following repeated episodes of diarrhoea. Often these symptoms don't appear on their own, and dogs may also feel ill, weak, vomit and lose their appetite. Nothing is more alarming than the sight of any amount of blood in their faeces, therefore, owners normally take their pets to the vet immediately. This way you can identify the cause and find the right treatment at once. But what causes these symptoms? This condition, known as haemorrhagic gastroenteritis (HGE) consists in the inflammation of the gastrointestinal tract that causes a leakage of blood into the bowel. The cause is uncertain, but some risk factors have been identified: it is most common in small-size, hyperactive, or stressed dogs. Obviously, if neglected, this condition can be dangerous for two main reasons: diarrhoea can quickly lead to severe dehydration, while the loss of blood can cause anaemia. But don't worry, the diagnosis is simple and once the treatment starts, your dog will be fine. Once the symptoms and the amount of blood in the faeces have been identified, all the vet has to do is take a blood sample to check the hematocrit (PCV), i.e. the red cells count.