Diverticulitis: who to see and what helps

Diverticulitis · Kitchener, Waterloo & Cambridge

Diverticulitis is inflammation or infection of small pouches in the wall of the large bowel. A flare is a medical matter first: it needs a physician or nurse practitioner, and sometimes a hospital. Food comes in on either side of that: clear liquids for comfort while a flare is at its worst, then a fibre-rich diet to lower the risk of another, with no need to avoid nuts or seeds. At CARESPACE that part starts with a Registered Dietitian.

What diverticulitis is

Diverticula are small bulges or pouches that form in the wall of the large bowel. Most people get some as they get older, and most never have symptoms: that symptom-free state is called diverticulosis. Diverticulitis is what happens, in a small number of people who have the pouches, when they become inflamed or infected. “Diverticular disease” is the umbrella term for diverticulosis, bleeding from a pouch and diverticulitis. The Canadian Digestive Health Foundation estimates that more than 130,000 Canadians have it.

The symptoms can overlap with irritable bowel syndrome, colitis and bowel cancer, so a new pain of this kind needs a medical assessment first.

Symptoms of diverticulitis

• Pain in the lower left side of the abdomen; a small number of people feel it on the right
• In diverticulitis, pain that is severe and constant
• A high temperature
• Bleeding, or passing mucus, from the rectum
• Constipation or diarrhea
• Bloating
• In milder diverticular disease, pain that gets worse after eating and eases after a bowel movement or passing gas

What causes diverticulitis

Age comes first: about half of Canadians over 80 have diverticular disease. Too little fibre is thought to produce small stools and high pressure inside the colon, which pushes the lining out through weak spots in the muscle. Roughly half the risk of diverticulitis itself is put down to genes. Obesity, particularly around the waist, weight gain and smoking raise the risk, and physical activity lowers it, especially when it is vigorous.

Regular use of anti-inflammatory painkillers raises the risk too. Regular means twice a week or more, so the ibuprofen taken after most shifts on a plant or warehouse floor counts. Nuts, corn and popcorn are not on the list: eating them is not linked with a higher risk.

How diverticulitis is diagnosed

A physician or nurse practitioner starts with your symptoms and an examination, and may order blood tests or a stool sample. A CT scan should be considered to confirm diverticulitis when it has not been confirmed on imaging before, and to look for complications when someone is very unwell. A colonoscopy is advised after a complicated episode and after a first uncomplicated one, unless you had a good-quality colonoscopy within the past year. It is delayed for six to eight weeks, or until the symptoms have fully settled, whichever is longer.

When diverticulitis needs urgent care

Call 911 or go to an emergency department if you, or someone you are caring for, has severe abdominal pain together with vomiting, a swollen abdomen, or being unable to pass stool or gas; is bleeding heavily from the rectum, has red or maroon blood mixed with the stool, or has any bleeding with light-headedness; or is acting confused, has pale or blotchy skin, has a very high or very low temperature, or is breathless or breathing fast. That last group can be signs of sepsis.

The emergency departments in Waterloo Region are:

• WRHN @ Midtown (formerly Grand River Hospital), 835 King St. W., Kitchener
• WRHN @ Queen’s Blvd. (formerly St. Mary’s General Hospital), 911 Queen’s Blvd., Kitchener
• Cambridge Memorial Hospital, 700 Coronation Blvd., Cambridge

If you cannot get there safely, call 911.

See a physician or nurse practitioner the same day, or go to an urgent care clinic, if there is mucus in your stool, or a small amount of blood with a bowel movement and none of the emergency signs above; if abdominal pain is getting worse or does not go away; if you have a high temperature or feel hot, cold or shivery; if you keep vomiting and cannot keep fluids down; if diarrhea has lasted more than seven days; or if vomiting has lasted more than two days. If you are being treated for a flare and still cannot move beyond clear liquids after three to five days, follow up with whoever is treating you immediately.

These are the lists the NHS, the UK’s health service, gives for emergency care and for an urgent appointment, with two bleeding signs added to the emergency list. Bleeding with light-headedness comes from the Canadian Digestive Health Foundation. Red or maroon blood mixed with the stool is a sign of bleeding for which the National Institute of Diabetes and Digestive and Kidney Diseases in the United States says to seek medical help right away (its list is for bleeding in the stomach), and our Digestive Issues & Gut Health page treats it as an emergency too. For diverticular disease the NHS asks for an urgent appointment for any blood in the stool, so even a small amount is a same-day sign here.

What the evidence says about treating diverticulitis

The American Gastroenterological Association’s 2021 expert review gives “best practice advice”, which is not graded for strength. In the UK’s NICE guideline the verb carries the strength: “offer” marks a strong recommendation, and “consider” one where the evidence of benefit is less certain. NICE gives its diet, fibre and painkiller advice for diverticulosis and diverticular disease (the pouches, with or without symptoms), not specifically for the time after diverticulitis.

• Clear liquids while the flare is at its worst. The expert review advises a clear liquid diet during the acute phase of uncomplicated diverticulitis. The goal is comfort, and the diet should advance as symptoms improve.
• A high-quality diet afterwards. To reduce the risk of another episode, the advice is a diet high in fibre from fruits, vegetables, whole grains and legumes. A fibre supplement is not a replacement for it. NICE advises that the benefits of more fibre may take several weeks and that a high-fibre diet should be kept up for life if tolerated.
• Nuts, seeds and popcorn are fine. NICE: there is no need to avoid seeds, nuts, popcorn or fruit skins.
• Weight, activity and smoking. People who have had diverticulitis should reach or keep a normal body mass index, be routinely active and not smoke.
• Painkillers. Avoid regular use of anti-inflammatories; aspirin prescribed to prevent a second heart attack or stroke is the stated exception. NICE advises avoiding anti-inflammatories and opioid painkillers if possible, because they may increase the risk of a perforation.
• Antibiotics are not automatic. In otherwise healthy people with mild, uncomplicated diverticulitis they can be used selectively, and NICE says to consider not prescribing them for people who are otherwise well. They are advised for people who are frail or have other conditions, who are vomiting or not improving, and for complicated diverticulitis.
• Three products are advised against for preventing the next one. People who have had diverticulitis should not be treated with 5-aminosalicylic acid, probiotics or rifaximin to prevent recurrence, and NICE says not to offer an aminosalicylate or antibiotics for that purpose.
• Surgery is a personal decision. It should not be advised on the number of episodes alone, and it reduces the risk of another episode without removing it.

What a physician or hospital may offer

CARESPACE does not provide scans, hospital care or surgery, but it helps to know where they fit. Signs of a complication (an abscess, a perforation, a blockage, a fistula into the bladder or vagina, or sepsis) mean same-day hospital assessment, which can lead to intravenous antibiotics, drainage of an abscess or surgery. Only about 1% of people with diverticular disease need surgery.

How each CARESPACE service helps with diverticulitis

Nutrition & Dietitian

Food goes through three stages around a flare, and a Registered Dietitian can take you through each: what counts as clear liquids while your physician or nurse practitioner is treating the flare, how to step back up to ordinary meals as the pain settles, and how to build fibre gradually afterwards, with enough fluid, to keep gas and bloating down. If you have been avoiding nuts, seeds, popcorn or berries since your first flare, they can help you bring them back. Canada’s Gastrointestinal Society suggests a registered dietitian for a personalized plan.

See our dietitians →

Nurse Practitioner

A Nurse Practitioner can assess lower abdominal pain, order bloodwork, decide with you whether antibiotics are needed and prescribe them, advise on pain relief that avoids anti-inflammatories, and refer you for imaging or a follow-up colonoscopy. The signs in the urgent section above, fever with abdominal pain among them, still mean same-day care or an emergency department, not a booked appointment.

See our Nurse Practitioner service →

Other services people ask about

Naturopathic Medicine. Probiotics are what people most often ask about. The expert review’s advice is that people who have had diverticulitis should not be treated with probiotics to prevent another episode, and none of the sources we read supports an herbal product or supplement for it. Talk to a pharmacist, physician or nurse practitioner before taking a product for your bowel.

Where most people start

With a diagnosis. If this is new, or you think a flare is starting, see a physician or nurse practitioner first and use the urgent section above. Once a flare is being treated, or you have had one and want to lower the odds of another, start with a Registered Dietitian.

How your team works together

At CARESPACE, diverticulitis is mostly one service: a dietitian, working alongside whoever is managing the medical side, whether that is a Nurse Practitioner or your own physician.

Browse by service: dietitians and Nurse Practitioner.

What to expect at your first visit

1. What happened. When your flare or flares were, how they were treated, and any CT or colonoscopy results you can bring.
2. What you eat now, including anything you dropped after a flare, such as nuts, seeds or high-fibre foods.
3. Your bowel habit and fluids. Constipation, diarrhea, and how much you drink in a day.
4. A plan to leave with, matched to where you are: mid-flare, recovering, or preventing the next one.

What you can do at home

• During a flare, follow the advice of whoever is treating you. Clear liquids are for the worst days, not for weeks.
• Afterwards, increase fibre gradually and drink plenty of water.
• Eat a balanced diet with whole grains, fruit and vegetables. There are no specific foods you need to avoid.
• Stay active and do not smoke.
• For pain, NHS advice is acetaminophen (paracetamol), not ibuprofen or codeine. A pharmacist can help you choose.

Outlook

Mild diverticulitis usually responds to treatment, and many episodes do not come back. In the expert review’s figures, about 8% of people have a recurrence within a year of recovering from a first episode and about 20% within 10 years. A complicated episode is most often the first one, and the risk of complications goes down with later episodes. Lingering symptoms are common: in one trial of uncomplicated diverticulitis, about 45% of participants reported periodic abdominal pain a year later, and ongoing pain should be checked for continuing inflammation with a scan and a scope. None of the sources gives a typical length for a flare. The pouches themselves do not go away.

Diverticulitis treatment in Kitchener, Waterloo and Cambridge

Kitchener. Nutritionist & Dietitian in Kitchener. Locations: Victoria North, Fischer-Hallman, Westmount East and Deer Ridge.

Waterloo. Nutritionist & Dietitian in Waterloo and Nurse Practitioner in Waterloo. Locations: Weber North, Uptown Waterloo and Waterloo GoodLife.

Cambridge. Nutritionist & Dietitian in Cambridge. Location: Hespeler Road.

The city pages linked above show the locations and practitioners for each service, with their next availability.

Common questions

Can I eat nuts, seeds and popcorn with diverticulitis?

Yes. Eating nuts, corn or popcorn is not linked with a higher risk of diverticulitis, and NICE’s advice for diverticulosis and diverticular disease is that there is no need to avoid seeds, nuts, popcorn or fruit skins.

What should I eat during a diverticulitis flare?

Clear liquids while it is at its worst, for comfort, moving back to ordinary food as symptoms improve. Moving on faster is acceptable if you feel able to.

Do I always need antibiotics?

Not always. For otherwise healthy people with mild, uncomplicated diverticulitis, antibiotics can be used selectively. That decision belongs to the physician or nurse practitioner who assesses you.

Is diverticulitis the same as diverticulosis?

No. Diverticulosis means the pouches are there without symptoms. Diverticulitis means they have become inflamed or infected.

Is there a dietitian for diverticulitis in Cambridge?

Yes. See Nutritionist & Dietitian in Cambridge, or book online or call 519-208-2273 and our Central Reception Team will find the closest location with an opening.

Do I need a referral?

No. Book online or call 519-208-2273. You pay at each visit and receive a receipt for your extended health plan. More on fees and insurance →

Sources

• Peery AF, Shaukat A, Strate LL. AGA Clinical Practice Update on Medical Management of Colonic Diverticulitis: Expert Review. Gastroenterology, 2021.
• National Institute for Health and Care Excellence. Diverticular disease: diagnosis and management (NG147). 2019. Its wording is explained in Making decisions using NICE guidelines.
• Canadian Digestive Health Foundation. Diverticular Disease. Updated June 2025.
• Gastrointestinal Society (badgut.org). Diverticular Disease. No date given on the page.
• NHS. Diverticular disease and diverticulitis. Reviewed September 2023; its next review was due in September 2026. Source for the urgent and emergency lists.
• National Institute of Diabetes and Digestive and Kidney Diseases. Gastritis & Gastropathy. Last reviewed August 2019. Source for red or maroon blood mixed with the stool as an emergency sign.

Related conditions

Digestive Issues & Gut Health
Irritable Bowel Syndrome
Constipation
Crohn’s & Colitis

Ready to book?

Book online with a Registered Dietitian, or call 519-208-2273 and our Central Reception Team will match you with the right person and the closest location.

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