Blood in the stool

What does blood in the stool mean?

Blood in the stool refers to visible or invisible traces of blood in the stool, which may indicate bleeding in the gastrointestinal tract. Sometimes the blood is mixed with the stool, causing it to appear red or black. In other cases, the blood may lie on top of the stools and coat them. There are also situations where the blood is not visible to the naked eye and is present only in minute traces in the stools. Doctors refer to this as occult blood, which can only be detected through specialised tests.

The causes of blood in the stools are varied and range from harmless bleeding caused by haemorrhoids or anal fissures to serious conditions such as bowel cancer. The colour of the blood can provide clues as to the source of the bleeding: red blood often indicates bleeding in the middle or lower part of the gastrointestinal tract, whilst black blood usually points to bleeding in the upper part.

It is important to see a doctor promptly if you notice blood in your stools. They can determine whether a serious condition is present or whether the issue is a more harmless problem such as anal fissures or haemorrhoids. Early treatment is also important in these cases to prevent long-term problems.

What are some possible causes of blood in the stools?

Not every stool that is red or black in colour is a cause for alarm. Foods such as beetroot, spinach, blueberries or liquorice can cause similar discolouration. Certain medicines, such as charcoal or iron tablets, can also turn the stool black.

What are the possible causes of blood in the stool?

The causes of blood in the stools are varied and range from haemorrhoids and anal fissures to serious conditions such as bowel cancer. In principle, any injury to the digestive tract can lead to blood in the stools. This starts in the mouth and throat and extends through the oesophagus, stomach, small intestine and large intestine to the anus.

What are the most common causes of blood in the stools?

• Haemorrhoids: Swelling of the blood vessels in the rectum or around the anus, which can be caused by straining during bowel movements, constipation or pregnancy.
• Anal fissures: Tears or ulcers in the lining of the anus, which often occur after passing hard stools, such as those caused by constipation.
• Chronic inflammatory bowel diseases: Conditions such as Crohn’s disease or ulcerative colitis, which, alongside other symptoms, can also cause blood in the stool.
• Stomach and intestinal ulcers: These are the most common cause of bleeding in the upper digestive tract.
• Diverticulitis: Diverticula are pouches that protrude from the bowel wall. If they become inflamed, they can sometimes bleed.
• Bowel cancer: Bleeding caused by tumours in the bowel. These tumours are not always malignant; even benign growths in the bowel can cause blood in the stools.

Other possible causes of blood in the stools include:

• Various infections of the gastrointestinal tract
• Chronic heartburn
• Liver disease
• Stomach cancer
• Long-term use of certain medicines: one example is acetylsalicylic acid (ASA).

What does blood in the stool look like?

Blood in the stools is categorised according to the different forms in which it appears, with the colour in particular often providing clues as to the underlying cause. (The consistency and colour of the blood in the stools also depend on the severity of the bleeding and bowel activity.)

• Bright red blood: This fresh blood often indicates bleeding in the middle or lower part of the digestive tract, such as in the large bowel or rectum. It is bright red because it has not been in contact with digestive juices for long.
• Dark red blood or blood clots: This type of blood in the stool may indicate bleeding in the upper digestive tract, such as the stomach or duodenum. Contact with digestive juices causes the blood to turn dark red or form clots.
• Black blood: Black, tar-like blood usually indicates bleeding in the upper digestive tract, between the oesophagus and the duodenum. The blood has mixed with digestive juices, causing it to turn black. This is known as ‘tarry stools’ (melena).

In addition, blood may be visible on the surface of formed stools. This may indicate injuries to the rectum, anus or anal canal.

How is a diagnosis made when there is blood in the stools?

Diagnosis begins with a detailed medical history, during which the doctor asks about previous illnesses, medication and dietary habits. This is followed by a physical examination, which in this case is carried out rectally. To identify the source of the bleeding, a gastroscopy or a colonoscopy may also be necessary. Stool and blood samples are also analysed. In some cases, ultrasound scans of the abdominal wall and nuclear medicine procedures are also used. These investigations are crucial for identifying the underlying condition.

How is blood in the stools treated?

The treatment for blood in the stools depends on the underlying condition. In most cases, treatment is required to stop the bleeding and address its cause.

• Haemorrhoids: First- and second-degree haemorrhoids are usually treated with special ointments or suppositories. For more severe haemorrhoids, surgical removal may be necessary.
• Anal fissures: These are often treated with suppositories and ointments, as well as measures to regulate bowel movements. In some cases, Botox injections or surgery may be necessary.
• Chronic inflammatory bowel diseases: Conditions such as Crohn’s disease or ulcerative colitis usually require treatment with anti-inflammatory medication such as glucocorticoids (cortisone).
• Diverticulitis: In mild cases, rest and specific dietary advice are prescribed; in severe diverticulitis, antibiotics and a fasting regimen may be necessary. In some cases, surgery is required.
• Bowel cancer: Comprehensive treatment of the tumour is necessary, which may vary depending on the stage and location of the tumour.
• Stomach cancer: Here, too, comprehensive treatment of the tumour is required.
• Stomach and oesophageal disorders, as well as liver diseases: These are usually treated with medication.
• Medication-related bleeding: Medicines that can cause blood in the stools (aspirin, NSAIDs, blood thinners) should only be taken under medical guidance and supervision.

What are the causes of blood in the stools in babies?

Blood in a baby’s stools can have many different causes. Small tears at the anal opening often occur, particularly with diarrhoea or constipation. Other possible reasons for blood in a baby’s stools include swallowing blood whilst teething or breastfeeding, allergic reactions or bowel polyps. Infections of the gastrointestinal tract can also lead to blood in a baby’s stools.

How can blood in the stool be prevented? Tips and measures

Preventing blood in the stool depends on the underlying causes. For common triggers such as haemorrhoids and anal fissures, a high-fibre diet and regular exercise can be helpful. For conditions such as diverticulosis, inflammatory bowel disease or bowel cancer, regular screening is crucial for early detection and timely treatment.

General tips for preventing blood in the stool:

• Healthy diet: Ensure you eat a balanced diet with plenty of fruit, vegetables and wholegrains.
• Fluid intake: Make sure you drink enough fluids.
• Physical activity: Exercise regularly to promote bowel health.
• Avoiding risk factors: Avoid nicotine and alcohol, as these can increase the risk of bowel cancer.
• Regular check-ups: If you have a family history of the condition, regular medical check-ups are particularly important.

When to see a doctor and which doctor?

Blood in the stools should always be investigated by a doctor. Your GP can be your first point of contact and may subsequently refer you to a gastroenterologist or proctologist.