Free guide · Scarlet Beast En español →
Diverticulosis and diverticulitis: the symptoms, getting a diagnosis, treatment, and food
For anyone with pain low on the left side of the belly, anyone told that a scan or a colonoscopy found pouches in the colon, and anyone who has had diverticulitis and wants to keep it from coming back. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, part of the NIH) says diverticulosis means small pouches that push outward through weak spots in the wall of the colon; that more than 70 percent of people over 80 have it; that most people with it never have symptoms; and that less than 5 percent develop diverticulitis, when the pouches become inflamed. This page passes on, by name, what NIDDK says: the symptoms and when it cannot wait, what may play a role and who gets it, the tests, treatment at home and in the hospital, pain medicines, surgery, and food, including why most people no longer need to avoid nuts, popcorn and seeds. It builds the words to say to a doctor, and prints a card to keep.
Right now
- A lot of blood from your rectum, or blood with dizziness or fainting: call 911 (ours). NIDDK says diverticular bleeding may be severe and life-threatening.
- Severe belly pain, or belly pain with fever, or vomiting so you cannot keep liquids down? Go to the emergency room now (ours). Pain low on the right side can be appendicitis.
- Any bleeding from your rectum, even a small amount? See a doctor right away (NIDDK).
More help
- Other belly troubles: An upset stomach: find the right page · Appendicitis · Irritable bowel syndrome (IBS) · Constipation in adults · Peptic ulcers · Gallstones.
- What can lower the risk: When you want to quit smoking · When you need food.
- Care and costs: When you need a doctor and can’t pay · My medicines list · Symptom diary · Get ready for your appointment.
- In a crisis: Help right now (988, 911). All our free tools.
An upset stomach, and not sure this is the right page? The pages on this site for throwing up, diarrhea, heartburn and constipation, on one list.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor or nurse has reviewed it. The facts were read on October 16, 2026 on NIDDK’s Diverticulosis & Diverticulitis pages (NIH): the overview, Definition & Facts, Symptoms & Causes, Diagnosis, Treatment and Eating, Diet, & Nutrition (last reviewed August 2021). Ours: calling 911 for a lot of blood from the rectum, or blood with dizziness or fainting; the emergency room for severe belly pain, belly pain with fever, or vomiting so you cannot keep liquids down; calling back the same day when treated at home if things get worse; that ibuprofen, naproxen and aspirin are NSAIDs, and not stopping a prescribed medicine on your own; that pain low on the right can be appendicitis; adding fiber after a flare, and low-cost fiber; health centers, food banks and SNAP when money is tight; and the order of the steps. What we left out: brand names, the names and doses of antibiotics, research studies, and clinical pages for providers. This page saves nothing and loads no trackers.