Causes of rectal bleeding after a bowel movement

Bright-red blood on toilet paper or on the outside of stool may come from the anus or lower rectum, especially after straining or passing a hard stool. Diarrhoea, cramps or fever can occur with gastroenteritis, Crohn's Disease or Ulcerative Colitis. Diverticular Disease can also cause bleeding from the bowel.

Darker blood, blood mixed through stool, black stool, a change in bowel habit, weight loss or persistent tiredness needs clinical review. Bowel Cancer, Rectal Cancer, polyps and less common bowel conditions can present with bleeding, but the appearance of blood cannot identify the cause by itself.

Note the colour and amount you see, whether it is on paper or mixed with stool, and whether pain, diarrhoea, constipation or abdominal symptoms accompany it. Arrange a medical assessment for repeated bleeding, unexplained bleeding or a change in bowel habit.

Until assessed, avoid straining and keep hydrated if you can drink normally. Do not assume that painless bleeding is harmless. A clinician may examine the area and decide whether stool tests, blood tests or further bowel assessment are appropriate. Polyp Removal may be discussed if a polyp is found.

Seek urgent help for heavy or continuing bleeding, black or tar-like stool, dizziness, fainting, severe abdominal pain, repeated vomiting, confusion or unusual weakness. These signs can indicate significant blood loss or a serious bowel problem.

Ask where the bleeding may be coming from, whether your medicines or bowel pattern could contribute, and which tests are appropriate. Tell the clinician about previous bowel conditions, family history and any change in stool shape or frequency.