Treating acute diverticulitis

Photo of doctor examining a patient’s abdomen (PantherMedia /

Diverticulitis can usually be treated effectively. In straightforward (uncomplicated) cases, antibiotics often aren’t needed. Surgery is only necessary if the inflammation is so severe that it could lead to complications.

Diverticulitis is a condition where bulging pouches arise in the lining of the large intestine and then become inflamed or infected. These pouches, known as diverticula, are often harmless and may go unnoticed. But diverticulitis causes symptoms such as pain in the lower left side of the abdomen (tummy), fever and digestive problems. There are two types of diverticulitis:

  • Uncomplicated diverticulitis: Diverticula and the surrounding intestinal lining are inflamed but there are no signs of pus building up (abscesses) or the inflammation spreading.
  • Complicated diverticulitis: Abscesses have formed. Sometimes the inflammation has even already spread or the wall of the intestine has torn (intestinal perforation). The intestine may also become blocked or the inner lining of the tummy may become inflamed (peritonitis).

About 80% of people who have diverticulitis have the uncomplicated form, and about 20% have the complicated form.

Acute diverticulitis that has been successfully treated may come back again after some time. The risk of this happening is greater after having the complicated form.

In the past, acute diverticulitis was generally treated with antibiotics, and surgery was often recommended if it kept coming back. Nowadays clinical guidelines advise doctors to only use these treatments when absolutely necessary. Painkillers like ibuprofen or diclofenac (NSAIDs: non-steroidal anti-inflammatory drugs) shouldn’t be used to treat diverticulitis because they can increase the likelihood of complications such as intestinal perforations. 

How is uncomplicated diverticulitis treated?

In about 95 out of 100 people, uncomplicated diverticulitis goes away on its own within a week. In about 5 out of 100 people, the symptoms stay and treatment is needed. Surgery is only rarely necessary.


The use of antibiotics can sometimes be avoided in uncomplicated diverticulitis – but only if an ultrasound or CT scan has been done and no abscesses were found. Then antibiotics probably wouldn’t reduce the risk of complications. In one large study, about 1 out of 100 participants had an abscess or an intestinal perforation – regardless of whether or not they had taken antibiotics. In rare cases, though, these scans may fail to discover abscesses or perforations.

Antibiotics are generally only recommended for the treatment of uncomplicated diverticulitis if there’s an increased risk of complications – for instance if someone has chronic kidney disease, a weakened immune system, high blood pressure or allergies. Due to a lack of studies on treatment with antibiotics in high-risk patients, it’s not yet possible to say how effective antibiotics really are in those cases.

Medical check-ups

In uncomplicated diverticulitis, it’s important to see a doctor regularly – particularly in the first few days – in order to detect any complications early enough. The doctor can do blood tests to monitor the level of inflammation in your body, for example. The treatment is often possible on an outpatient basis (without a hospital stay).

Serious complications are rare in uncomplicated diverticulitis. But it’s still important to look out for warning signs, including severe abdominal pain, fever, a hard and tense tummy, and nausea. Symptoms like this should be checked out by a doctor as soon as possible.


Some doctors advise people to try to carry on eating normally – or to eat a low-fiber diet for a while. Others recommend mainly eating soups or other non-solid foods, as well as drinking enough fluids, in the first few days. It’s not clear whether it really is better to avoid solid foods for a while. There aren’t any good studies in this area.

How is complicated diverticulitis treated?

In about 80 out of 100 people, complicated diverticulitis clears up within a few weeks of having treatment with antibiotics. About 20 out of 100 people have surgery.


Complicated diverticulitis is treated in hospital. Antibiotics are needed in order to stop the inflammation from spreading further. They can be used in the form of a syrup, tablets, or an infusion (drip).


Whether or not people with complicated diverticulitis should avoid solid foods will depend on their symptoms and the results of diagnostic tests. They are often given water, tea and soup for a few days, and then gradually start eating normally again. If they aren’t able to drink enough, they are given fluids through a drip.


About 15 out of 100 people who have complicated diverticulitis have a pus-filled abscess. If necessary, the pus can be drained out of the body through a thin tube.


If the symptoms don’t improve within a few days, the risk of serious complications increases. Surgery is then recommended. People who already have an intestinal perforation or peritonitis need to have surgery immediately. Both of these conditions are medical emergencies.

Even if a long-lasting infection with pus goes away after treatment with antibiotics, doctors still often recommend operating on the bowel. The aim of this surgery is to prevent people from developing diverticulitis again. Research has shown that almost half of all people who have previously had successful treatment with antibiotics go on to develop diverticulitis again within a few years – and new episodes sometimes lead to serious complications. People who have a weakened immune system or chronic kidney disease are also at higher risk of serious complications.