Finding blood in one’s stools can be alarming for many people, and this is entirely understandable. Although there are often harmless reasons behind this, it is important to take it seriously, as it may be an early sign of more serious illnesses. The most important thing is not to panic, but to see a doctor to find out the exact cause of the bleeding.
In this article, we provide a detailed overview of everything you need to know about blood in the stools, based on the latest medical knowledge as of 2025. Our aim is to provide clear, easy-to-understand information to help you understand the possible causes, diagnostic procedures and treatment options. The Endomedix Gastroenterology Centre Our specialists are committed to helping their patients by applying the latest scientific findings.
What could be causing blood in the stools?
Blood in the stools can take various forms, and the colour and amount of blood, as well as whether it is mixed with the stools, can provide important information to the doctor about the site of the bleeding and its possible cause.
- Haematochezia (fresh, red blood): This usually indicates bleeding from the lower part of the digestive system, most commonly from the large intestine or the rectum. The blood is bright red, as it has not had time to be digested.
- Melaena (black stools): Black, tar-like, sticky stools with a characteristically unpleasant odour are a sign of upper gastrointestinal bleeding (oesophagus, stomach, upper small intestine). The blood turns black as a result of the action of stomach acid and digestive enzymes.
- Occult (hidden) bleeding: This refers to bleeding that is not visible to the naked eye but can only be detected through laboratory testing (a faecal occult blood test). It is often the first sign of bowel cancer or polyps.
The most common causes of bleeding
There are a number of conditions that can cause blood in the stools. Below, we list the most common causes, starting with the less serious ones and moving on to the more serious ones.
Haemorrhoids (Nodus haemorrhoidalis)
Haemorrhoids are one of the most common causes of fresh, red bleeding from the rectum. It typically appears as drops on the surface of the stool, on toilet paper or in the toilet bowl. Haemorrhoids are dilated veins around the anus, which can easily be damaged during bowel movements. Although unpleasant, they are generally not a serious condition.
Anal fissure (Fissura ani)
A small but extremely painful tear in the mucous membrane of the anus. The bleeding is also bright red, but the amount is small, and it is accompanied by severe, stabbing pain during and after a bowel movement.
Diverticulosis and Diverticulitis
Diverticula are small, pouch-like bulges in the wall of the large bowel. Diverticulosis itself (the presence of these bulges) is often asymptomatic. Problems arise when they become inflamed (diverticulitis) or when the blood vessels within them rupture. Diverticular bleeding can result in sudden, profuse, painless bleeding and requires hospital treatment.
Inflammatory bowel diseases (IBD)
The two most common inflammatory bowel diseases are ulcerative colitis and Crohn’s disease.
- Ulcerative colitis: A chronic inflammation of the large intestine, one of the main symptoms of which is bloody, mucous diarrhoea.
- Crohn's disease: It can affect any part of the digestive system, and although bloody stools are less common than in ulcerative colitis, they can occur.
Polyps and colorectal cancer (colorectal carcinoma)
Colonic polyps are benign growths that develop on the wall of the bowel and may become malignant over time. Both polyps and established bowel cancer can cause bleeding. This bleeding is often hidden (occult), but may also appear as visible blood. This is why screening is particularly important, especially for those aged 45 and over.
Vascular abnormalities (Angiodysplasia)
Abnormal dilation of the blood vessels in the walls of the digestive tract is more common in older people. These angiodysplasias are fragile and may bleed easily, usually without causing pain.
Causes relating to the upper alimentary tract
Stomach and duodenal ulcers, oesophageal varices (particularly in cases of liver cirrhosis) or stomach tumours can also cause bleeding. In such cases, the stools are typically black (melaena), but in the event of heavy, rapid bleeding, fresh blood may also appear in the stools.
Making a diagnosis: What can you expect at the doctor’s?
When you consult a doctor about bloody stools, the diagnostic process involves several steps. The aim is to pinpoint the source of the bleeding. The Endomedix Gastroenterology Centre In every case, our specialists draw up an examination plan that causes the least possible discomfort, taking the patient’s individual circumstances into account.
1. Taking a medical history and conducting a physical examination
The doctor will ask you in detail about your symptoms:
- When did you first notice the blood?
- What colour is it, and how much?
- What other symptoms do you have (abdominal pain, diarrhoea, constipation, weight loss, fever)?
- Are you taking any medication (e.g. anticoagulants, non-steroidal anti-inflammatory drugs)?
- Have you ever had similar symptoms, or is there a history of digestive disorders in your family?
During the physical examination, the doctor will examine your abdomen and carry out a digital rectal examination (DRE), which allows them to feel for haemorrhoids and tumours in the lower rectum.
2. Laboratory tests
A blood count test helps to determine whether the bleeding has caused anaemia. Elevated levels of inflammatory markers (e.g. CRP) may indicate inflammatory bowel disease. The immunochemical test (FIT) for detecting occult blood in the stool is extremely sensitive and specific for screening for colorectal cancer.
3. Endoscopic examinations
Endoscopy is the most accurate method of locating the source of bleeding. A thin, flexible tube (endoscope) is inserted into the body; at the end of the tube there is a camera and a light source.
- Colonoscopy (colonoscopy of the colon): This is the most important examination in cases of blood in the stools. It allows the entire large bowel and the final section of the small bowel to be examined. During the examination, it is not only possible to diagnose abnormalities (e.g. polyps, tumours, inflammation), but also to take a tissue sample and even to remove polyps. Many people are apprehensive about this examination, but it can now be carried out under general anaesthesia, making it completely painless.
- Gastroscopy (gastroscopy of the stomach): In the event of tarry stools, or if a colonoscopy has failed to identify the cause, a gastroscopy is performed to examine the upper gastrointestinal tract (oesophagus, stomach and duodenum).
4. Imaging studies
In certain cases, particularly where there is active, severe bleeding, and if an endoscopy cannot be performed or proves unsuccessful, a CT angiogram may be required. This is a CT scan using contrast medium, which makes the bleeding vessel visible.
Modern treatment options in 2025
Treatment always depends on the cause of the bleeding. The Endomedix Gastroenterology Centre uses the most up-to-date, evidence-based therapeutic approaches.
- Haemorrhoids and anal fissures: Initially, lifestyle changes (a high-fibre diet, drinking plenty of fluids) and topical treatments (suppositories, ointments) may help. In persistent cases, minimally invasive outpatient procedures may be considered, such as rubber band ligation or laser treatment.
- Diverticular bleeding: In most cases, the bleeding stops on its own. In the event of severe, persistent bleeding, endoscopic haemostasis (e.g. placement of a clip) or an interventional radiology procedure (vessel occlusion) may be required.
- Removal of polyps: Polyps detected during a colonoscopy can be removed immediately (polypectomy), thereby preventing the development of cancer. This is a painless procedure.
- Inflammatory bowel diseases: The aim of treatment is to reduce inflammation and achieve a symptom-free state. To this end, specialised anti-inflammatory drugs, immunosuppressants and modern biological therapies are used, in accordance with the „treat-to-target” principle.
- Cancer: The treatment of bowel cancer depends on the stage of the tumour. In the early stages, endoscopic removal may be sufficient. In more advanced cases, a combination of surgery, chemotherapy and radiotherapy is required.
- Peptic ulcer disease: Medicines that reduce stomach acid production (proton pump inhibitors, PPIs) and – where there is an underlying Helicobacter pylori infection – antibiotic treatment form the basis of therapy. In the event of active bleeding, endoscopic haemostasis is performed.
When should you see a doctor immediately?
Although immediate treatment is not usually required in most cases, certain symptoms do require urgent medical attention:
- Heavy, sudden bleeding
- Dizziness, weakness, feeling faint
- Paleness, cold sweats
- Severe abdominal pain, fever, abdominal distension
- Haemoptysis
These symptoms may indicate severe, life-threatening blood loss, so you should call an ambulance immediately or go to the nearest A&E department.
Prevention is your responsibility
The most serious condition underlying bloody stools – bowel cancer – can be prevented. The most effective way to prevent it is through regular screening. According to international and national guidelines, everyone over the age of 45 is advised to undergo bowel screening, even if they have no symptoms. The most accurate method for this is a colonoscopy, which enables the timely detection and removal of polyps, which are considered a precancerous condition.
Don’t let fear or uncertainty hold you back! Modern medicine offers gentle and effective methods of diagnosis and treatment. Blood in your stools is an important signal from your body that should not be ignored.
If you have experienced similar symptoms or have any questions, please do not hesitate to contact the Endomedix Gastroenterology Centre Our specialists are on hand to carry out a thorough examination to identify the cause of your symptoms and provide you with the most appropriate treatment.
