Blood in Stool

You may assume that bright red blood always comes from piles, or that dark stool is simply caused by food. The colour and position of blood provide clues, but they cannot establish the cause. Bleeding may come from the anus, rectum, colon or higher digestive tract.

Blood may appear in several forms You may notice blood on toilet paper, red streaks on the surface of stool, pink or red toilet water, blood mixed through stool, blood with mucus, bloody diarrhoea, dark red stool, black, sticky or tar like stool, or blood clots. Bleeding from the bottom is also called rectal bleeding, although the source may be elsewhere in the digestive tract. A small, one off amount is often caused by a minor condition, but persistent, recurrent or unexplained bleeding needs assessment. Colour provides a clue, not a diagnosis Bright red blood often comes from the anus, rectum or lower bowel because it has had less time to change colour. Darker blood may have travelled further or been mixed through stool. Melaena describes black, sticky or tar like stool caused by digested blood, commonly from bleeding higher in the gastrointestinal tract. Upper gastrointestinal bleeding can present with vomiting blood or dark, sticky stool. However, rapid heavy upper gastrointestinal bleeding can sometimes appear red, iron tablets and some foods can darken stool, and beetroot and other strongly coloured foods can resemble blood. A visual impression cannot safely determine the source. Black or dark red stool requires urgent clinical advice. Haemorrhoids are common but should not be assumed Haemorrhoids, also called piles, are enlarged blood vessels in or around the anus. They may cause bright red blood after opening the bowels, blood on paper or the outside of stool, itching, a lump, discomfort, or mucus. Haemorrhoids are common and non cancerous. However, finding piles does not automatically prove that all bleeding comes from them. Persistent bleeding, a change in bowel habit, weight loss, anaemia or abdominal symptoms still requires appropriate assessment. An anal fissure usually causes pain An anal fissure is a small tear in the lining of the anus. A typical pattern may include sharp pain while passing stool, burning pain lasting afterwards, bright red blood on paper or stool, and recent constipation or hard stool. NHS guidance describes severe sharp pain during bowel movements, continuing burning pain and bright red bleeding as common fissure features. This pattern is suggestive but not diagnostic. A clinician may need to examine the area. Constipation can contribute to bleeding Hard stool and straining can contribute to fissures and haemorrhoids. Measures that may reduce recurrence include adequate fluid intake, gradually increasing dietary fibre where appropriate, regular physical activity, responding to the urge to open your bowels, avoiding prolonged straining, and using prescribed laxatives correctly. Not all bleeding associated with constipation comes from a fissure or piles. New or persistent bleeding still needs review. Bloody diarrhoea suggests a different group of causes Blood mixed with loose stool may occur with gastrointestinal infection, inflammatory bowel disease, reduced blood flow to the bowel, diverticular disease, medicine related inflammation, or other bowel disease. Associated features may include abdominal cramps, fever, vomiting, mucus, urgency, recent antibiotics, recent travel, or contact with someone who has diarrhoea. Bloody diarrhoea requires urgent GP or NHS 111 assessment. Do not use anti diarrhoeal medicines without professional advice when blood or fever is present. Inflammatory bowel disease can cause recurrent symptoms Inflammatory bowel disease includes Crohn's disease and ulcerative colitis. Possible features include recurrent diarrhoea, blood or mucus, abdominal pain, urgency, tiredness, weight loss, and symptoms outside the bowel. These symptoms overlap with infection and other bowel conditions. Diagnosis requires clinical assessment and appropriate testing. Diverticular bleeding can be substantial Diverticula are small pouches that can form in the wall of the large bowel. They may cause painless bleeding, sometimes in a considerable amount. Diverticular disease can also cause abdominal pain or inflammation. Sudden large volume bleeding, whether painful or painless, requires emergency assessment. Polyps and bowel cancer are possible causes Blood in stool can occur with colorectal polyps or bowel cancer. Other possible features include a persistent change in bowel habit, stool becoming looser or more frequent, abdominal pain, unexplained weight loss, unusual tiredness, iron deficiency anaemia, a feeling of incomplete emptying, or an abdominal or rectal mass. These symptoms are common and often have non cancerous explanations. They still need investigation when persistent or unexplained. Age affects pathways, not whether concern is valid Current NICE guidance recommends quantitative FIT for adults with several symptom patterns, including a change in bowel habit, iron deficiency anaemia, an abdominal mass, rectal bleeding in people aged 50 or over. Rectal bleeding with unexplained abdominal pain or weight loss in adults under 50, and other specified combinations of abdominal symptoms, anaemia and weight loss. These criteria guide investigation and referral. They do not mean rectal bleeding below an age threshold should be ignored. Medicines can contribute to bleeding Medicines that may increase or worsen bleeding include anticoagulants, aspirin, other antiplatelet medicines, anti inflammatory painkillers, and some medicines affecting the stomach or bowel. An anticoagulant may make bleeding more visible or harder to stop. It does not prove that the medicine is the only cause. Tell the clinician the exact medicine, dose and timing, whether doses were missed or repeated, why you take it, and whether you have other bleeding or bruising. Do not stop an anticoagulant or antiplatelet medicine on your own. The risk of continued bleeding must be balanced against the reason it was prescribed. Amount and circulation determine immediate urgency Major blood loss may cause faintness, collapse, rapid heartbeat, pale, cold or clammy skin, breathlessness, confusion, marked weakness, or reduced urine. Visible bleeding that does not stop, a toilet bowl turning red or large clots requires A&E or 999. Do not wait to count exact episodes if you are becoming unwell. Your clinician builds a picture of your bleeding pattern Questions may include: When bleeding began. How often it has happened. Whether it is on the paper, coating stool or mixed through it. Whether the stool is black, dark red or bright red. Whether there are clots. Whether there is pain during bowel movements. Whether your bowel habit has changed. Whether there is diarrhoea, constipation or mucus. Whether you have abdominal pain or a lump. Whether you have lost weight. Whether you are unusually tired or breathless. Which medicines you take. Whether there is a bowel disease or cancer in the family. The aim is to choose the correct assessment rather than to make a diagnosis from colour alone. Examination is explained and requires consent Assessment may include checking heart rate and blood pressure, looking for pallor or dehydration, feeling the abdomen, inspecting the anal area, and a digital rectal examination. During a digital rectal examination, a clinician gently inserts a gloved, lubricated finger into the rectum to assess for blood, tenderness or a lump. You should receive an explanation and be offered privacy. You can request a chaperone and discuss clinician gender preferences where services can accommodate them. Blood tests may assess the effect and possible cause Possible blood tests include full blood count, iron studies, kidney and liver function, inflammation markers, clotting tests, and other tests guided by symptoms. A normal blood count does not explain the bleeding. Anaemia may indicate ongoing or repeated blood loss but can also have other causes. FIT detects small amounts of human blood A faecal immunochemical test, or FIT, measures human haemoglobin in a small stool sample. It can help identify who may benefit from urgent colorectal investigation. FIT does not identify the exact source, diagnose cancer by itself, diagnose piles or fissures, replace clinical assessment, or guarantee that serious disease is absent. NICE recommends referral on a suspected colorectal cancer pathway when a symptomatic FIT result is at least 10 micrograms of haemoglobin per gram of faeces. A negative FIT does not cancel persistent symptoms If FIT is below the referral threshold, safety netting remains necessary. NICE states that referral should not be delayed when strong clinical concern remains because of continuing unexplained symptoms or findings. Return for review when bleeding continues or recurs, symptoms worsen, you develop weight loss, bowel habit remains changed, anaemia develops, a lump is found, or you become generally unwell. A previous negative NHS bowel screening test also does not replace assessment of new symptoms. Further investigation depends on the suspected source Possible tests include stool tests for infection or inflammation, flexible sigmoidoscopy, colonoscopy, CT imaging, upper gastrointestinal endoscopy, and examination under anaesthesia in selected anal conditions. A colonoscopy uses a flexible camera to examine the lining of the large bowel. The choice depends on your bleeding pattern, examination, FIT result, age, health problems in the family and other symptoms. Do not let embarrassment delay assessment Rectal bleeding is a common reason for healthcare contact. Clinicians are accustomed to discussing bowel habit, examining the anus and arranging stool tests. Clear descriptions help assessment. Useful information includes a photograph of the stool or toilet water if safely and privately obtained, the number of episodes, whether blood was mixed with stool, changes in bowel habit, and your medicines list. Do not handle or transport stool unless you have been given an appropriate sample container and instructions. Children with blood in stool need assessment Blood in a child's stool has age specific causes and should be discussed with a GP. In babies and young children, the response depends on feeding, growth, abdominal symptoms, fever, overall wellbeing and the amount of blood. Large bleeding, black stool, severe pain, lethargy or a very unwell child requires urgent assessment.

Blood in stool should be assessed through five questions: how much blood is present, what does it look like, is it continuing, what symptoms accompany it, and what health conditions and medicines change the risk. The immediate priority is recognising major blood loss; the next priority is identifying the source rather than assuming the colour provides the diagnosis.