What Is Radiation Enteritis? A Plain-Language Guide to the Intestine Irritation That Follows Radiation Therapy

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026

Quick Answer: Radiation Enteritis at a Glance

Radiation enteritis is inflammation of the intestines caused by radiation therapy aimed at the abdomen, pelvis or rectum [1]. It causes diarrhea, nausea, vomiting and stomach cramps that usually go away several weeks after treatment ends, though a chronic form can develop months or years later [1]. Treatment manages symptoms with diet changes and medications, with surgery in severe cases [1] [2].

Feature	Details
What it is	Inflammation of the intestines after radiation therapy, caused by irritation of the intestines from the radiation [1].
What it feels like	Diarrhea, nausea, vomiting, and stomach cramps. Symptoms usually go away several weeks after treatment ends [1].
Who gets it	People receiving radiation aimed at the abdomen, pelvis, or rectum, most commonly for cancers in the belly and pelvic areas [1].
When it is more serious	If it lasts longer, it can cause anemia or bowel obstruction, and it may develop months or years after treatment as chronic radiation enteritis [1].
How it is treated	Managing symptoms until they go away: diet changes, medications for diarrhea and pain, antibiotics for bacterial overgrowth, and in severe cases a feeding tube or surgery [1] [2].

What the research says

• Radiation enteritis is not rare, and late effects can appear years later. A review of radiation enteritis reports that about one in five people treated with abdominal or pelvic radiation therapy will show clinical signs of it, such as obstruction, malabsorption, or malnutrition. Acute symptoms are managed symptomatically and regress when radiation stops, while late toxicity can occur up to 30 years afterward. This was a narrative review, not a trial. (Loge et al., J Visc Surg, 2020) [3]

• It may be under-recognized. A clinical review concluded that radiation enteritis appears to be more common than originally thought because patients underreport it and clinicians lack awareness. It noted that patient-related and treatment-related risk factors have been identified and should be modified where possible, and that experimental therapies still need large human trials. This was also a narrative review. (Hale, Curr Opin Gastroenterol, 2020) [4]

What Is Radiation Enteritis, in Plain Language?

Radiation enteritis is inflammation of the intestines that occurs after radiation therapy [1].

It is most common in people receiving radiation therapy for cancer in the abdomen and pelvic areas [1], because the radiation used to treat those cancers can pass through, or land near, the intestines along the way.

What Does Radiation Enteritis Feel Like?

The symptoms of radiation enteritis include diarrhea, nausea, vomiting, and stomach cramps [1]. They occur because of irritation of the intestines from radiation therapy for cancer [1].

Symptom	What it looks like
Diarrhea	Loose or watery stools.
Nausea	Feeling sick to your stomach.
Vomiting	Throwing up.
Stomach cramps	Painful, cramping sensations in the belly.

How Long Do the Symptoms Last?

For most people, radiation enteritis is temporary. Symptoms usually go away several weeks after treatment ends [1], as the intestines heal.

Sometimes symptoms last longer, and radiation enteritis that goes on for longer can cause anemia and bowel obstruction [1]. In some people the condition continues long after radiation therapy ends, or develops months or years after treatment [1]. This longer-lasting form is called chronic radiation enteritis.

Who Is at Higher Risk?

The risk of radiation enteritis is higher in people having radiation treatment for cancers in the belly and the pelvis [1], because the radiation in those treatments travels near or through the intestines.

Can Radiation Enteritis Lead to Other Problems?

Yes. Radiation enteritis that goes on for longer can cause complications. Chronic radiation enteritis can cause anemia, diarrhea, or bowel obstruction [1].

Complication	What it means
Anemia	The body doesn’t have enough healthy red blood cells to carry oxygen, which can leave you tired.
Bowel obstruction	A blockage that stops food and liquid from moving normally through the intestines.
Long-term diarrhea	Ongoing loose stools in chronic radiation enteritis [1].

How Is Radiation Enteritis Diagnosed?

Radiation enteritis diagnosis may start with your medical history, details of your radiation therapy and a physical exam, followed by tests of the digestive tract [2]. Your doctor will want to know what radiation therapy you received, where it was aimed, and when. From there, several tests can look inside your digestive tract:

Test or procedure	What it does
Medical history and physical exam	A discussion of your symptoms and radiation treatment, plus a physical exam [2].
Endoscopy	A long flexible tube with a camera is passed down your throat to see inside your small intestine [2].
Colonoscopy	A long flexible tube with a camera is passed through your rectum to look at your large intestine [2].
Capsule endoscopy	A pill-sized camera that you swallow creates pictures of your intestines [2].
Imaging tests	X-rays, a CT scan, or an MRI scan to get pictures of the area [2].

How Is Radiation Enteritis Treated?

Radiation enteritis treatment usually involves managing its symptoms until they go away [2]. Because this condition is irritation of the intestines after radiation therapy, treatment focuses on keeping you comfortable while the inflammation heals. Your health care provider might recommend:

Treatment	How it helps
Changes to diet	Adjusting what you eat to ease irritation of the intestines.
Medications for diarrhea	Slowing or reducing diarrhea while the intestines heal.
Medications for pain	Relieving stomach cramps and discomfort.
Antibiotics	Treating an overgrowth of bacteria in the intestines [2].
Feeding tube	May be needed if radiation enteritis lasts longer [2].
Surgery	Sometimes used to bypass the part of the intestine that is irritated [2]. In severe cases, surgery to remove sections of the intestine may be necessary [1].

What is the bottom line on radiation enteritis?

Radiation enteritis is inflammation of the intestines that follows radiation therapy aimed at the abdomen, pelvis, or rectum [1]. For most people, the diarrhea, nausea, vomiting, and stomach cramps ease within several weeks after treatment ends [1] as the inflammation heals. When symptoms last longer, or appear months or years later as chronic radiation enteritis, they deserve medical attention because they can lead to anemia or bowel obstruction [1]. Treatment is focused on helping you: diet changes, medications for diarrhea and pain, antibiotics for bacterial overgrowth, and, when needed, a feeding tube or surgery [2]. If you are going through radiation therapy and your belly starts troubling you, tell your care team. Managing symptoms early is the fastest route to relief.

Going through radiation or recovering from it? If you develop diarrhea, nausea, vomiting, or stomach cramps, don’t brush it off as a side effect you have to live with. Talk to your health care provider. Simple steps such as diet changes and medication can ease the symptoms, and if the trouble lasts longer, treatments such as antibiotics, a feeding tube, or surgery are there to help you heal.

Frequently Asked Questions

What is radiation enteritis in simple terms?

Radiation enteritis is inflammation of the intestines that occurs after radiation therapy [1]. Radiation therapy for cancer irritates the intestines, causing symptoms such as diarrhea, nausea, vomiting, and stomach cramps [1].

What are the symptoms of radiation enteritis?

The symptoms are diarrhea, nausea, vomiting, and stomach cramps. They occur because of irritation of the intestines from radiation therapy for cancer [1].

Why does radiation cause intestine inflammation?

Radiation aimed at the abdomen, pelvis, or rectum can irritate the intestines along the way [1]. The risk is higher in people having radiation treatment for cancers in the belly and the pelvis [1].

Does radiation enteritis go away?

For most people it is temporary, and inflammation usually subsides several weeks after treatment ends [1]. For some, it continues long after radiation therapy ends or develops months or years after treatment [1].

Can radiation enteritis cause serious problems?

Yes. Radiation enteritis that goes on for longer can cause anemia and bowel obstruction [1]. Chronic radiation enteritis can cause complications such as anemia, diarrhea, or bowel obstruction [1].

How is radiation enteritis diagnosed?

Diagnosis might start with a discussion of your medical history and a physical exam [2]. Doctors may also use endoscopy, colonoscopy, capsule endoscopy, or imaging tests such as X-rays, a CT scan, or an MRI scan [2].

What treatments help radiation enteritis?

Treatment usually involves managing symptoms until they go away [2]. Your provider might recommend diet changes and medications for diarrhea and pain [2]. Antibiotics can treat an overgrowth of bacteria [2]. If it lasts longer, you might need a feeding tube, and sometimes surgery is used to bypass the irritated part of the intestine [2].

When is surgery needed for radiation enteritis?

In severe cases, tube feeding or surgery to remove sections of the intestine may be necessary [1]. Surgery is also sometimes used to bypass the part of the intestine that is irritated [2].

References

1. Mayo Clinic Staff. Radiation enteritis - Symptoms and causes. Mayo Clinic. Published April 6, 2024. https://www.mayoclinic.org/diseases-conditions/radiation-enteritis/symptoms-causes/syc-20355409

2. Mayo Clinic Staff. Radiation enteritis - Diagnosis and treatment. Mayo Clinic. Published April 6, 2024. https://www.mayoclinic.org/diseases-conditions/radiation-enteritis/diagnosis-treatment/drc-20449450

3. Loge L, et al. Radiation enteritis: Diagnostic and therapeutic issues. J Visc Surg. 2020;157(6):475-485. PMID 32883650. https://doi.org/10.1016/j.jviscsurg.2020.08.012

4. Hale MF. Radiation enteritis: from diagnosis to management. Curr Opin Gastroenterol. 2020;36(3):208-214. PMID 32141897. https://doi.org/10.1097/MOG.0000000000000632

Medical disclaimer

This article is for informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.