ConditionDigestive system
Diverticulosis
Diverticulosis means having small pouches (diverticula) that bulge outward through weak spots in the wall of the colon, most often the sigmoid colon on the lower left. It is very common with age, found in more than half of people over 60, and most people never have symptoms. It is often discovered by chance on a colonoscopy or CT scan. A small minority develop complications: inflammation or infection (diverticulitis) or bleeding. A high-fiber diet, exercise and not smoking lower that risk.
Also called: Colonic diverticulosis, diverticular disease (when symptomatic), colon pouches
At a glance
- What it is
- Small pouches in the colon wall, usually without symptoms.
- How common
- Increases with age: present in over half of people over 60.
- Risk factors
- Age, low-fiber diet, obesity, inactivity, smoking, some medicines (NSAIDs, steroids, opioids).
- Complications
- Diverticulitis (inflamed pouches) and diverticular bleeding, each in a minority.
- Treatment
- None needed without symptoms; high-fiber diet, fluids and exercise reduce complications.
When to get help
Call 911 or go to the ER
- Large amounts of bright red or maroon blood from the rectum, especially with dizziness or fainting
- Severe abdominal pain with a rigid belly, high fever or vomiting
See a doctor within a day or two
- Constant pain in the lower left belly with fever, nausea or change in bowel habit (possible diverticulitis)
- Any new rectal bleeding
- Pain with urinary symptoms, passing air or stool in urine, or foul vaginal discharge (possible fistula)
Book a routine appointment
- Intermittent bloating, cramping or changes in bowel habit
- Diverticulosis found on a scan or colonoscopy, to discuss prevention
- Due for colorectal cancer screening
What diverticulosis is
The colon wall has small weak points where blood vessels pass through the muscle layer. Over many years, pressure inside the colon pushes the inner lining out through these gaps, forming pouches 5 to 10 mm across. In Western countries, most pouches form in the sigmoid colon (lower left). In Asia, right-sided diverticula are more common.
Terms explained
| Term | Meaning |
|---|---|
| Diverticulum | A single pouch |
| Diverticulosis | Having pouches, usually without symptoms |
| Symptomatic uncomplicated diverticular disease | Pouches with ongoing symptoms like pain or bloating, without inflammation |
| Diverticulitis | Inflammation or infection of pouches |
| Diverticular bleeding | Bleeding from a blood vessel at a pouch |
| Diverticular disease | Umbrella term for symptoms or complications |
Symptoms
Most people with diverticulosis have no symptoms. Some have:
- intermittent cramping or aching in the lower left belly
- bloating and gas
- constipation or alternating bowel habits
These symptoms overlap with irritable bowel syndrome, and it is often unclear whether the pouches are the cause.
Causes and risk factors
- Age: the colon wall weakens with age.
- Low fiber intake: associated with harder stools and higher colon pressure, though evidence is mixed.
- Obesity, especially central obesity.
- Physical inactivity.
- Smoking.
- Medicines: NSAIDs, aspirin, steroids and opioids increase the risk of complications, particularly bleeding and perforation.
- Genetics: a family history increases risk.
- Connective tissue disorders such as Ehlers-Danlos and Marfan syndromes in younger people.
Complications
Diverticulitis
A minority of people with diverticulosis develop diverticulitis over their lifetime, causing constant lower left belly pain, fever, nausea and tenderness. It can lead to abscesses, perforation, fistulas or narrowing.
Diverticular bleeding
A blood vessel stretched over a pouch can rupture, causing sudden, painless passage of a large amount of red or maroon blood. Most bleeding stops on its own, but some people need a transfusion, colonoscopy treatment, or embolization. NSAIDs and blood thinners increase the risk.
Diagnosis
Diverticulosis is usually found incidentally:
- Colonoscopy: shows pouch openings.
- CT scan: shows pouches and is the main test for diverticulitis.
- Barium enema: older test, rarely used now.
After an episode of diverticulitis, a colonoscopy is often advised if you have not had a recent one, to rule out colorectal cancer, which can look similar on CT.
Treatment and diet
No symptoms
No treatment is needed. Focus on lowering the risk of complications.
Diet
- Increase fiber to about 25 to 35 grams a day from vegetables, fruits, whole grains, beans and lentils. Increase gradually to limit gas.
- A fiber supplement such as psyllium if diet alone is not enough.
- Drink plenty of fluids.
- Nuts, seeds and popcorn are fine. Older advice to avoid them is not supported by evidence; studies found no increase, and possibly lower, risk of diverticulitis in people who eat them.
- Limit red and processed meat, which is associated with higher risk.
Lifestyle
- regular physical activity
- maintain a healthy weight
- stop smoking
- avoid regular NSAID use if possible
Symptomatic diverticular disease
Fiber, antispasmodics and treatments used for IBS may help ongoing symptoms.
Outlook
Most people with diverticulosis live without problems. Lifestyle measures reduce the chance of complications. If diverticulitis or bleeding occurs, most episodes are treated without surgery.
Frequently asked questions
What is diverticulosis?
Diverticulosis is the presence of small pouches that bulge outward through weak spots in the wall of the colon. It is very common with age and usually causes no symptoms. It is often found during a colonoscopy or CT scan done for another reason.
What is the difference between diverticulosis and diverticulitis?
Diverticulosis means you have pouches in your colon, usually without symptoms. Diverticulitis means one or more pouches have become inflamed or infected, causing pain, fever and tenderness, usually in the lower left belly. Only a minority of people with diverticulosis develop diverticulitis.
What foods should I avoid with diverticulosis?
You do not need to avoid nuts, seeds, corn or popcorn; research shows they do not increase risk. It helps to eat more fiber and less red and processed meat. A diet rich in vegetables, fruit, whole grains and legumes is recommended.
Can diverticulosis go away?
No. Once pouches form, they remain. But most people never have symptoms or complications. A high-fiber diet, regular exercise, a healthy weight and not smoking reduce the risk of problems.
Is diverticulosis serious?
Usually not. Most people never know they have it. A minority develop diverticulitis or bleeding, which can be serious. Seek care for persistent lower belly pain with fever, or for any rectal bleeding.
Sources
This guide was written from current patient and clinical guidance, including:
- American Gastroenterological Association: Clinical practice update on medical management of colonic diverticulitis (2021)
- American Society of Colon and Rectal Surgeons: Clinical practice guidelines for left-sided colonic diverticulitis (2020)
- NIDDK: Diverticular disease
- NHS: Diverticular disease and diverticulitis
- MedlinePlus: Diverticulosis and diverticulitis