Overview
Tuberculosis (TB) is an infection caused by the bacterium Mycobacterium tuberculosis. It usually affects the lungs, but it can also infect other organs. When it affects the digestive system, it most often involves the end of the small intestine (ileum) and the first part of the large bowel (caecum). It can cause ulcers, thickening and narrowing of the bowel, and sometimes affects the lining of the abdomen (peritoneum) or nearby lymph nodes. TB outside the lungs is usually less contagious than lung TB.
Symptoms
Long-lasting belly pain, often in the lower right side
Weight loss and loss of appetite
Fever, often low-grade, and night sweats
Diarrhoea or constipation, or alternating between them
Blood in the stool (less common)
A lump in the right lower belly, bloating or swelling of the belly from fluid
Tiredness and anaemia
Self-Care Tips
Treatment is long, so plan reminders for taking medicines and keep supplies at hand
Follow-up continues after treatment to make sure the disease is gone
Talk to your doctor about any worries, including stigma; TB is a medical illness and is treatable
When to See a Doctor
Seek medical care promptly if you notice: Severe belly pain, a hard swollen belly, repeated vomiting, or being unable to pass stool or wind; Heavy rectal bleeding, black tarry stools, dizziness or fainting; Fever with a swollen, painful belly; Cough lasting more than three weeks, coughing blood, or breathlessness; Jaundice, severe headache, confusion or neck stiffness during treatment.
Why it happens
The bacteria reach the bowel by swallowing coughed-up infected sputum, by spread from the lungs or through the blood, or, rarely, from contaminated unpasteurised milk. Not everyone exposed to TB becomes ill; the immune system often controls the germ for years, and the disease may appear later if immunity weakens.
How common it is
It is much more common in parts of the world where TB is widespread, and in people with weakened immunity such as those with HIV, diabetes, malnutrition, or those taking immune-suppressing drugs. In other places it is uncommon and is often mistaken for other bowel diseases.
How it is diagnosed
Diagnosis can be difficult because intestinal TB looks very like Crohn's disease. Doctors combine symptoms, blood tests, a chest X-ray, TB skin or blood tests, CT or MR scans of the bowel, and a colonoscopy with biopsies. The biopsies are tested for typical TB changes, TB bacteria on stains and culture, and genetic tests. Sometimes tissue or fluid from the abdomen is needed. If doubt remains, doctors may start a trial of anti-TB treatment and check for improvement, since the wrong treatment (for example steroids or immune-suppressing drugs for presumed Crohn's) can be harmful.
Lifestyle and daily habits
Treatment is done with prescribed medicines. These steps help recovery and protect others.
• Take every dose at the same time each day and never stop early, even if you feel well
• Attend all follow-up visits and blood tests, which monitor the liver and your response
• Avoid alcohol while on treatment, as it increases the risk of liver injury
• Household members and close contacts may need to be checked; follow public health advice
• If you also have lung TB, cover your mouth when coughing and ventilate rooms until your doctor says you are no longer infectious
Diet
Good nutrition supports healing, particularly if you have lost weight.
• Eat small, frequent, balanced meals with enough calories and protein
• If the bowel is narrowed, your doctor or dietitian may advise a low-fibre diet for a time
• Take vitamin supplements only as prescribed; vitamin B6 is sometimes given with some TB medicines
• Drink only pasteurised milk and dairy products
Medicines
Combination anti-TB medicines are the cure. Your doctor chooses and monitors them.
• A combination of several anti-TB medicines is used together, usually for around six months
• Common effects include stomach upset and orange-coloured urine; report any yellow skin or eyes, dark urine, vision changes, severe rash or persistent vomiting at once
• Tell your doctor about all your other medicines, because some anti-TB drugs interact with many others
• Do not use steroids or immune-suppressing drugs unless your doctor knows about the TB
Procedures and surgery
Procedures help with diagnosis and complications.
• Colonoscopy with biopsies to confirm the diagnosis and exclude Crohn's disease
• Imaging such as CT or MR enterography to see the bowel and lymph nodes
• Endoscopic dilation (widening) or surgery for a stricture, blockage, perforation or bleeding that does not settle
• Draining fluid from the abdomen when it collects, to test it and to relieve symptoms
Outlook
Intestinal TB is curable with a full course of anti-TB medicines, usually taken for around six months, though your doctor may adjust the length. Most people improve within weeks. Surgery is needed only for complications such as blockage or perforation. Finishing every dose is essential to avoid the TB returning or becoming drug-resistant, which is much harder to treat.
Questions to ask your doctor
• How sure are you that this is TB and not Crohn's disease?
• Do I also have TB in my lungs and can I spread it to my family?
• How long is the treatment and what side effects should I look out for?
• Which blood tests will be needed to monitor my liver?
• Do my family members need to be checked?
Source and review
This guide comes from the Saudi Gastroenterology Association (SGA) patient library, prepared by the Approved for publication by SGA; individual clinician review is ongoing. Last reviewed: 2026-04-24. It is for education and does not replace your doctor's advice.
Frequently Asked Questions
What is Intestinal Tuberculosis?
How is Intestinal Tuberculosis diagnosed?
What is the outlook for Intestinal Tuberculosis?
When should I see a doctor about Intestinal Tuberculosis?
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