How common is blood in stool in anal fissure?

An anal fissure is a small tear in the lining at the opening of the anus. Passing a hard or large stool can stretch the area and reopen the tear. Blood is commonly bright red and may be seen on toilet paper or the stool surface. Sharp pain during a bowel movement, followed by burning or aching, is a useful clue to discuss with a clinician. Other causes of bleeding can look similar, so the symptom alone cannot confirm a fissure.

Aim for soft, easy-to-pass stools by drinking fluids, including fibre-rich foods if suitable for you, and avoiding straining. A warm bath may ease discomfort around the anus. Clean gently with water or soft, unscented material rather than vigorous wiping. Arrange a medical review if this is new bleeding, if pain is substantial, or if symptoms do not settle. A clinician can check whether a fissure is present and discuss treatments that relax the surrounding muscle or improve stool consistency.

Seek urgent help if bleeding is heavy, the stool is black and sticky, you feel faint, or pain is severe and rapidly worsening. Contact a clinician promptly when bleeding keeps returning, blood seems mixed through the stool, or you also have fever, abdominal pain, persistent diarrhoea, or an unexplained change in bowel habit. These features may need assessment for causes beyond a simple fissure.

Ask whether the bleeding pattern and pain fit a fissure, how to prevent hard stools, and what treatment is suitable if it does not heal. Tell them about constipation, diarrhoea, childbirth, bowel disease, and medicines that affect bleeding.