Faeces that vary from normal in their odour, colour, content, or consistency. Abnormal faeces can be a symptom of a disorder of the digestive system or related organ, such as the liver. A change in the character of faeces however is more often due to a change in diet.
Diarrhoea (constant passage of liquid or very loose faeces) can often simply be caused by anxiety. Nonetheless, it can be the result of an intestinal infection (such as gastroenteritis), irritable bowel syndrome or an intestinal disorder (such as crohn’s disease or ulcerative colitis). Loose stools can also be an indication of malabsorption (effected absorption of nutrients by the small intestine).
Constipation (infrequent passage of very hard faeces) is usually harmless. Constipation that develops unexpectedly, however, can be caused by a disorder of the large intestine, such as cancer.
Pale faeces can be caused by diarrhoea, a lack of bile in the intestine due to bile duct obstruction, or diseases that causes malabsorption (such as coeliac disease). With malabsorption, the paleness is caused by the high fat content of the faeces. This type of faeces can be foul smelling, oily, and hard to flush away.
Dark faeces can result from taking iron tablets. If the faeces are black, however, there could be bleeding in the upper digestive tract.
Faeces that contain disproportionate amounts of mucus are occasionally connected with irritable bowel syndrome or constipation. Dysentery, enteritis, or a tumour of the intestine can also lead to the passage of excess mucus, usually accompanied by blood.
Blood in the faeces changes in appearance depending on the site of bleeding. Bleeding from the stomach or duodenum, is often passed in the form of tarry, black faeces. Blood from the colon is red and is generally passed at the same time as the faeces.
Bleeding from the anus or rectum, which can be due to haemorrhoids (piles) or tumours, is often a bright red. Sometimes, however it may not even be visible.