Symptoms and when to see a doctor
Blood on the toilet paper: when to worry and when to book
By Dr Wong Nan-Yaw, MBBS (NUS), FRCS (Edinburgh). Published . 4 min read.
Bright red blood on the toilet paper is most often caused by piles or a small anal tear. Blood mixed into the stool, black stools, or bleeding with weight loss or a three-week bowel habit change needs a bowel cancer check (NHS). Dr Wong Nan-Yaw, a specialist colorectal surgeon since 2003, advises a visit whenever bleeding is new or keeps returning.
What causes bright red blood on the toilet paper?
Piles (haemorrhoids) and anal fissures cause most bright red bleeding seen on the paper or in the bowl. Both sit close to the anus, so the blood has not mixed with stool and stays bright red. Neither is dangerous in itself, and both respond well to treatment.
Piles are swollen cushions of tissue and blood vessels. They bleed painlessly when hard stool rubs against them. A fissure is a small tear in the anal lining, and it usually hurts sharply during and after a bowel movement.
When is blood a warning sign?
Blood is a warning sign when it is dark or mixed through the stool, or when it comes with other changes. The NHS lists blood in the poo, a lasting change in bowel habit, weight loss without trying, abdominal pain or a lump, and unusual tiredness as symptoms of bowel cancer.
- Dark red or black stools, or blood mixed through the stool
- A change in bowel habit that lasts three weeks or more
- Weight loss you cannot explain, or tiredness and breathlessness from anaemia
- A close relative with bowel cancer or polyps
- Age 50 or over: Singapore's national programme invites screening from this age
What will a colorectal surgeon check?
A colorectal surgeon asks about your bowel habit and family history, examines the anal area, and takes a short look inside with a small scope. If your age or symptoms call for it, a colonoscopy checks the whole bowel for polyps and cancer. Most patients leave the first visit with a clear answer and a plan.
Colonoscopy is done under sedation, takes about 20 to 40 minutes, and lets polyps be removed in the same sitting.
When is bleeding an emergency?
Go to an emergency department or call 995 if bleeding is heavy, if you feel dizzy or faint, or if you have severe abdominal pain or a fever with it. These signs suggest significant blood loss or a complication and should not wait for an appointment.
Sources
Medically reviewed by Dr Wong Nan-Yaw
MBBS (NUS), FRCS (Edinburgh). 33 years in medicine (since 1993), 23 years as an accredited specialist (since 2003) and 18 years in private practice at Mount Elizabeth (since 2008). Last reviewed 6 November 2026.
How this article is prepared
Statements are checked against the sources listed above. This article is general education and does not replace a consultation. It is reviewed and updated when guidance changes. In an emergency, call 995.