Health A to Z
Diverticular disease and diverticulitis are related digestive conditions that affect the large intestine (bowel).
Diverticula are small bulges or pockets that can develop in the lining of the intestine as you get older.
Most people with diverticula don't get any symptoms and only know they have them after having a scan for another reason.
When diverticula cause symptoms, such as pain in the lower tummy, it's called diverticular disease.
If the diverticula become inflamed or infected, causing more severe symptoms, it's called diverticulitis. You're more likely to get diverticular disease and diverticulitis if you don't get enough fibre in your diet.
This page covers:
Symptoms of diverticular disease include:
If your diverticula become infected and inflamed (diverticulitis), you may suddenly:
Contact your GP as soon as possible if you have symptoms of diverticular disease or diverticulitis.
If you've already been diagnosed with diverticular disease, you usually don't need to contact your GP – the symptoms can be treated at home.
After taking your medical history and listening to your symptoms, your GP may first want to rule out other conditions, such as irritable bowel syndrome (IBS), coeliac disease or bowel cancer. These often have very similar symptoms to diverticular disease.
This may involve blood tests. If necessary, you'll be referred for a colonoscopy, a CT scan or sometimes both.
A colonoscopy is where a thin tube with a camera at the end (a colonoscope) is inserted into your back passage and guided up into your bowel. The doctor will then look for any diverticula or signs of diverticulitis. You will be given a laxative beforehand to clear out your bowels.
A colonoscopy shouldn't be painful but can feel uncomfortable. You may be offered painkilling medication and a sedative to make you feel more relaxed and reduce any discomfort.
Sometimes, you may need to have a CT scan. This might be done instead of a colonoscopy or in combination with one (called a CT colonoscopy or virtual colonoscopy). For a CT colonoscopy, the scan is done after you've had the laxative.
Eating a high-fibre diet may help ease the symptoms of diverticular disease and prevent diverticulitis. Generally, adults should aim to eat 30g of fibre a day, but your GP will be able to give you a specific target based on your individual height and weight.
Good sources of fibre include fresh and dried fruits and vegetables, beans and pulses, nuts, cereals and starchy foods. Fibre supplements – usually in the form of sachets of powder that you mix with water – are also available from pharmacists and health food shops.
Find out how to get more fibre in your diet.
Gradually increasing your fibre intake over a few weeks and drinking plenty of fluids can help prevent side effects associated with a high-fibre diet, such as bloating and wind.
If you have diverticulitis, your GP may recommend that you stick to a fluid-only diet for a few days until your symptoms improve.
While you are recovering you should eat a very low-fibre diet to rest your digestive system. Once the symptoms have gone, you can return to your high-fibre diet.
Paracetamol can be used to relieve pain – aspirin or ibuprofen shouldn't be taken regularly as they can cause stomach upsets. Speak to your GP if paracetamol alone is not working.
You may be prescribed a bulk-forming laxative to help ease any constipation or diarrhoea.
Diverticulitis can usually be treated at home with antibiotics prescribed by your GP.
However, more serious cases of diverticulitis may need hospital treatment. In hospital, you will probably get injections of antibiotics, and be kept hydrated and nourished using a tube directly connected to your vein (intravenous drip). You may also be prescribed a stronger painkiller if paracetamol is not helping.
In rare cases, surgery may be needed to treat serious complications of diverticulitis.
Surgery usually involves removing the affected section of your large intestine. This is known as a colectomy. This is the treatment for rare complications such as fistulas, peritonitis or a blockage in your intestines.
After a colectomy, you may have a temporary or permanent colostomy, where one end of your bowel is diverted through an opening in your tummy.
If surgery is being considered, your doctor should discuss the benefits and the risks very carefully with you.
It's not known exactly why some people get diverticular disease, but it seems to be linked to age, diet and lifestyle, and genetics.
As you get older, the walls of your large intestine become weaker and the pressure of hard stools passing through your intestines can cause diverticula to form.
The majority of people will have some diverticula by the time they are 80 years old.
Not eating enough fibre is thought to be linked to developing diverticular disease and diverticulitis.
Fibre helps to make your stools softer and larger, so they put less pressure on the walls of your intestines.
Some other things that seem to increase your risk include:
You're more likely to develop diverticula if you have a close relative with diverticular disease, especially if they developed it before they were 50.
Symptoms of diverticular disease and diverticulitis include abdominal pain, bloating and a change in normal bowel habits.
If diverticula have been discovered during a camera test for another reason (colonoscopy) or during a CT scan, you may be worried about what this means.
However, if you have never had abdominal pain or bouts of diarrhoea, there is a 70-80% chance that you will never have any symptoms from them.
Diverticula are extremely common over the age of 70 and they do not increase your risk of cancer. It's thought that a high-fibre diet is likely to reduce the risk of any symptoms developing.
The most common symptom of diverticular disease is intermittent (stop-start) pain in your lower abdomen (tummy), usually in the lower left-hand side.
The pain is often worse when you are eating, or shortly afterwards. Passing stools and breaking wind (flatulence) may help relieve the pain.
Other long-term symptoms of diverticular disease include:
Another possible symptom of diverticular disease is bleeding dark purple blood from your rectum (back passage). This usually occurs after diarrhoea-like cramping pain, and often leads to hospital admission, but fortunately this is an uncommon complication.
Diverticular disease does not cause weight loss, so if you are losing weight, seeing blood in your stools or experiencing frequent bowel changes, see your GP.
Diverticulitis shares most of the symptoms of diverticular disease (see above). However, the pain associated with diverticulitis is constant and severe, rather than intermittent. It is most likely to occur if you have previously had symptoms of diverticular disease, and develops over a day or two.
Other symptoms of diverticulitis can include:
The pain usually starts below your belly button, before moving to the lower left-hand side of your abdomen.
In Asian people, the pain may move to the lower right-hand side of your abdomen. This is because East Asian people tend to develop diverticula in a different part of their colon for genetic reasons.
Contact your GP as soon as possible if you think you have symptoms of diverticulitis.
If you have symptoms of diverticular disease and the condition has previously been diagnosed, you do not usually need to contact your GP as the symptoms can be treated at home.
Read more about the treatment of diverticular disease.
If you have not been diagnosed with the condition, contact your GP so they can rule out other conditions with similar symptoms, such as:
Irritable bowel syndrome (IBS) can also cause similar symptoms to diverticular disease.
Diverticular disease is caused by small bulges in the large intestine (diverticula) developing and becoming inflamed. If any of the diverticula become infected, this leads to symptoms of diverticulitis.
The exact reason why diverticula develop is not known, but they are associated with not eating enough fibre.
Fibre makes your stools softer and larger, so less pressure is needed by your large intestine to push them out of your body.
The pressure of moving hard, small pieces of stools through your large intestine creates weak spots in the outside layer of muscle. This allows the inner layer (mucosa) to squeeze through these weak spots, creating the diverticula.
There is currently no clinical evidence to fully prove the link between fibre and diverticula. However, diverticular disease and diverticulitis are both much more common in Western countries, where many people do not eat enough fibre.
It is not known why only one in four people with diverticula go on to have symptoms of diverticulitis. Diverticular disease may be chronic low-level diverticulitis. The symptoms are very similar to irritable bowel syndrome (IBS) and may overlap.
However, factors that appear to increase your risk of developing diverticular disease include:
Exactly how these lead to developing diverticular disease is unclear.
Diverticulitis is caused by an infection of one or more of the diverticula.
It is thought an infection develops when a hard piece of stool or undigested food gets trapped in one of the pouches. This gives bacteria in the stool the chance to multiply and spread, triggering an infection.
Diverticular disease can be difficult to diagnose from the symptoms, alone because there are other conditions that cause similar symptoms, such as irritable bowel syndrome (IBS).
In some cases, you may be offered treatment for IBS and diverticular disease at the same time.
To make sure there is not a more serious cause of your symptoms, your GP may refer you for a colonoscopy, where a thin tube with a camera at the end (a colonoscope) is inserted into your rectum and guided into your colon. Before the procedure begins, you will be given a laxative to clear out your bowels.
A colonoscopy is not usually painful, but it can feel uncomfortable. You may be offered painkilling medication and a sedative beforehand to make you feel more relaxed and help reduce any discomfort.
Another technique for confirming the presence of diverticula is a computerised tomography (CT scan). A CT scan uses X-rays and a computer to create detailed images of the inside of the body.
As with a colonoscopy, you will be given a laxative to clear out your bowels before you have the CT scan.
Unlike a regular CT scan, the colonography scan involves a tube being inserted into your rectum, which is used to pump some air up into your rectum. The CT scan is then taken with you lying on your front, and again lying on your back.
You may need to have an injection of contrast dye before the scan, but this is not always necessary.
If you have had a previous history of diverticular disease, your GP will usually be able to diagnose diverticulitis from your symptoms and a physical examination. A blood test may be taken, because a high number of white blood cells indicates infection. If your symptoms are mild, your GP will treat it at home and you should recover within four days.
Further tests will be needed if you have no previous history of diverticular disease.
If you are unwell, your GP may refer you to hospital for blood tests and investigations. This is to look for complications of diverticulitis and to rule out other possible conditions, such as gallstones or a hernia.
An ultrasound scan may be used, as well as a CT scan.
A CT scan may also be used if your symptoms are particularly severe. This is to check whether a complication, such as a perforation or an abscess, has occurred.
Treatment options for diverticular disease and diverticulitis depend on how severe your symptoms are.
Most cases of diverticular disease can be treated at home.
The over-the-counter painkiller paracetamol is recommended to help relieve your symptoms.
Painkillers known as non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, are not recommended because they may upset your stomach and increase your risk of internal bleeding.
Eating a high-fibre diet may initially help to control your symptoms. Some people will notice an improvement after a few days, although it can take around a month to feel the benefits fully. Read more advice about using diet to improve the symptoms of diverticular disease.
If you have constipation, you may be given a bulk-forming laxative. These can cause flatulence (wind) and bloating. Drink plenty of fluids to prevent any obstruction in your digestive system.
Heavy or constant rectal bleeding occurs in about 1 in 20 cases of diverticular disease. This can happen if the blood vessels in your large intestine (colon) are weakened by the diverticula, making them vulnerable to damage. The bleeding is usually painless, but losing too much blood can be potentially serious and may need a blood transfusion.
Signs that you may be experiencing heavy bleeding (aside from the amount of blood) include:
If you suspect that you (or someone in your care) is experiencing heavy bleeding, seek immediate medical advice. Contact your GP at once. If this is not possible then call NHS 111 or your local out-of-hours service.
Mild diverticulitis can often be treated at home. Your GP will prescribe antibiotics for the infection and you should take paracetamol for the pain. It's important that you finish the complete course of antibiotics, even if you are feeling better.
Some types of antibiotics used to treat diverticulitis can cause side effects in some people, including vomiting and diarrhoea.
Your GP may recommend that you stick to a fluid-only diet for a few days until your symptoms improve. This is because trying to digest solid foods may make your symptoms worse. You can gradually introduce solid foods over the next two or three days.
For the three to four days of recovery, a low-fibre diet is suggested, until you return to the preventative high-fibre diet. This is to reduce the amount of faeces (poo) your large bowel has to deal with while it is inflamed.
If you have not been diagnosed with diverticular disease before, your GP may refer you for a test such as a colonoscopy or CT colonography after the symptoms have settled.
If you have more severe diverticulitis, you may need to go to hospital, particularly if:
If you are admitted to hospital for treatment, you are likely to receive injections of antibiotics and be kept hydrated and nourished using an intravenous drip (a tube directly connected to your vein). Most people start to improve within two to three days.
In the past, surgery was recommended as a preventative measure for people who had two episodes of diverticulitis as a precaution to prevent complications.
This is no longer the case, as studies have found that in most cases, risks of serious complications from surgery (estimated to be around 1 in 100) usually outweigh the benefits.
However, there are exceptions to this, such as:
If surgery is being considered, discuss both benefits and risks carefully with the doctor in charge of your care.
In rare cases, a severe episode of diverticulitis can only be treated with emergency surgery. This is when a hole (perforation) has developed in the bowel. This is uncommon, but causes very severe abdominal pain, which needs an emergency trip to hospital.
Surgery for diverticulitis involves removing the affected section of your large intestine. This is known as a colectomy. There are two ways this operation can be performed:
Open colectomies and laparoscopic colectomies are thought equally effective in treating diverticulitis, and have a similar risk of complications. People who have laparoscopic colectomies tend to recover faster and have less pain after the operation.
Emergency surgery when the bowel has perforated is more likely to be open and may result in a stoma being formed (see below).
In some cases, the surgeon may decide your large intestine needs to heal before it can be reattached, or that too much of your large intestine has been removed to make reattachment possible.
In such cases, stoma surgery provides a way of removing waste materials from your body without using all of your large intestine. It is known as "having a bag" as a bag is stuck to the skin on your belly and the faeces (poo) are collected in the bag.
Stoma surgery involves the surgeon making a small hole in your abdomen – known as a stoma. There are two ways this procedure can be carried out:
In most cases, the stoma will be temporary and can be removed once your large intestine has recovered from the surgery. This will depend on the situation when you had the operation. If it was an emergency operation, you may need a few months to recover before having surgery to reverse the stoma.
If a large section of your large intestine is affected by diverticulitis and needs to be removed, or if you have multiple other conditions that make major surgery a risk, you may need a permanent ileostomy or colostomy.
In general terms, elective (non-emergency) surgery is usually successful, although it does not achieve a complete cure in all cases. Following surgery, an estimated 1 in 12 people will have a recurrence of symptoms of diverticular disease and diverticulitis.
In an emergency setting, the success rate depends on how unwell you are when you require the operation.
Complications of diverticulitis affect one in five people with the condition. Those most at risk are aged under 50.
Some complications associated with diverticulitis are discussed below.
Around 15% of people with diverticular disease or diverticulitis experience bleeding, which is usually painless, quick and resolves itself in 70-80% of cases.
However, if the bleeding does not resolve itself, an emergency blood transfusion may be required due to excessive bleeding. If the bleeding is severe, you may need to be admitted to hospital for monitoring.
Diverticulitis can lead to the inflamed part of the bowel being in contact with the bladder. This may cause urinary problems, such as:
The most common complication of diverticulitis is an abscess outside the large intestine (colon). An abscess is a pus-filled cavity or lump in the tissue. Abscesses are usually treated with a technique known as percutaneous abscess drainage (PAD).
A radiologist (a specialist in the use of imaging equipment, such as computerised tomography (CT) scans) uses an ultrasound or CT scanner to locate the site of the abscess.
A fine needle connected to a small tube is passed through the skin of your abdomen (stomach) and into the abscess. The tube is then used to drain the pus from the abscess. A PAD is performed under a local anaesthetic.
Depending on the size of the abscess, the procedure may need repeating several times before all the pus has been drained. If the abscess is very small – usually less than 4cm (1.5in) – it may be possible to treat it using antibiotics.
Read more about treating abscesses.
A fistula is another common complication of diverticulitis. Fistulas are abnormal tunnels that connect two parts of the body together, such as your intestine and your abdominal wall or bladder.
If infected tissues come into contact with each other, they can stick together. After the tissues have healed, a fistula may form. Fistulas can be potentially serious as they can allow bacteria in your large intestine to travel to other parts of your body, triggering infections, such as an infection of the bladder (cystitis).
Fistulas are usually treated with surgery to remove the section of the colon that contains the fistula.
In rare cases, an infected diverticulum (pouch in your colon) can split, spreading the infection into the lining of your abdomen (perforation). An infection of the lining of the abdomen is known as peritonitis.
Peritonitis can be life-threatening, and requires immediate treatment with antibiotics. Surgery may also be required to drain any pus that has built up, and it may be necessary to perform a colostomy.
Read more about treating peritonitis.
If the infection has badly scarred your large intestine, it may become partially or totally blocked. A totally blocked large intestine is a medical emergency because the tissue of your large intestine will start to decay and eventually split, leading to peritonitis.
A partially blocked large intestine is not as urgent, but treatment is still needed. If left untreated, it will affect your ability to digest food and cause you considerable pain.
Intestinal blockage from diverticular disease is very rare. Other causes, such as cancer, are more common. This is one of the reasons your GP will investigate your symptoms.
In some cases, the blocked part can be removed during surgery.
However, if the scarring and blockage is more extensive, a temporary or permanent colostomy may be needed.
Eating a high-fibre diet may help prevent diverticular disease, and should improve your symptoms.
Your diet should be balanced and include at least five portions of fruit and vegetables a day, plus whole grains. Adults should aim to eat 18g (0.6oz) to 30g (1.05oz) of fibre a day, depending on their height and weight. Your GP can provide a more specific target, based on your individual height and weight.
It's recommended that you gradually increase your fibre intake over the course of a few weeks. This will help prevent side effects associated with a high-fibre diet, such as bloating and flatulence (wind). Drinking plenty of fluids will also help prevent side effects.
If you have established diverticular disease, it may be suggested that you avoid eating nuts, corn and seeds due to the possibility that they could block the diverticular openings and cause diverticulitis. People usually find out themselves if these foods cause symptoms. Probiotics have also been recommended, but evidence is lacking. Overall, there is a lack of good quality scientific evidence on how to prevent diverticular disease.
Good sources of fibre include
Once you have reached your fibre target, stick to it for the rest of your life, if possible.
More detailed information on sources of fibre is provided below.
Good sources of fibre in fresh fruit (plus the amount of fibre that is found in typical portions) include:
Good sources of fibre in dried fruit (plus the amount of fibre found in typical portions) include:
Good sources of fibre in vegetables (plus the amount of fibre found in typical portions) include:
Good sources of fibre in nuts (plus the amount of fibre found in typical portions) include:
Good sources of fibre in breakfast cereals (plus the amount of fibre found in typical portions) include:
Note – the "own-brand" equivalents of the cereals mentioned above should contain similar levels of fibre.
Good sources of fibre in starchy food (plus the amount found in typical portions) include:
Fibre supplements – usually in the form of sachets of powder you mix with water – are also available from pharmacists and health food shops. Some contain sweetener. A tablespoon of fibre supplement contains around 2.5g of fibre. If you require long-term fibre supplements, your GP can prescribe them.