Can gastroenteritis have long-term effects?

How long does it take for your gut to heal after gastroenteritis?

Gastroenteritis is an infection of the gut that's caused by a virus or bacteria. It's normally an unpleasant yet short-lived illness that results in abdominal cramps, diarrhoea, vomiting, and nausea.

The symptoms of gastroenteritis typically only last for a few days, and the chances are your gut will fully heal in a short time too. GP Dr Sanjay Mehta from The London General Practice explains:

"It will likely take longer than a few days for the inflammation in your gut wall to settle and for the gut microbiome - the good bacteria in your gut - to restore to its pre-infection state. The duration of this healing time will vary enormously, depending on the your pre-existing health and diet."

But for some people, gastroenteritis can have long-term effects. These are sometimes called gastroenteritis flare-ups - a term that can describe several different ongoing or long-term health problems that were triggered by the initial illness.

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What causes gastroenteritis?

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What causes gastroenteritis flare-ups?

Dr Ahmed Albu-Soda is a gastroenterologist based at The Princess Grace Hospital, part of HCA UK:

"Most flare-ups are not caused by repeated infections," he explains. "Instead, flare-ups often result from long-term complications of the initial gastroenteritis infection. This may interfere with the ecosystem of the good bacteria in your gut, causing what is called dysbiosis. The infection may also disturb the nerves of your gut and interfere with the normal communication between your brain and gut."

You have less chance of lasting gut damage if your general health is good. However, there are other important factors too, such as the specific type of bacteria or virus that caused your gastroenteritis.

What are the long-term effects of gastroenteritis?

Can gastroenteritis have long-term effects? According to our experts, the answer is yes. Some of the following health complications may be temporary, but they can still affect you for a long time after your infection has cleared up.

Irritable bowel syndrome (IBS)

The most common long-term complication of gastroenteritis is post-infectious irritable bowel syndrome (PI-IBS). It's thought that this may be triggered by the immune system's inflammation response to gastroenteritis. Damage to the nerves in your gut wall may also play a role, by causing unusual bowel movements and pain¹.

This affects around 10-30% of people with gastroenteritis. This form of IBS - unlike chronic IBS - is often temporary. Abbas Kanani, pharmacist at Chemist Click Online Pharmacy, explains the similarities and differences of PI-IBS and IBS.

"Symptoms for both include nausea, diarrhoea, stomach cramps, and constipation. Post-infectious IBS may last for months or even years after the infection. Although it's uncomfortable, having IBS doesn't increase the risk of other diseases or disorders after symptom resolution. It is possible for PI-IBS to go away without the need for treatment."

Chronic diarrhoea

Unlike diarrhoea as a normal, short-lived symptom of gastroenteritis, chronic diarrhoea lasts for weeks or even months after the infection has cleared up. It's rare to have persistent diarrhoea after gastroenteritis. If you do, this may be down to what caused your infection. For example, chronic diarrhoea is more likely if your gastroenteritis was caused by salmonella food poisoning. If it lasts more than six weeks, there is blood in the poo, weight loss, or you are unwell - see your doctor for a review.

Patient picks for Abdominal pain

Digestive health

What causes gastroenteritis?

Gastroenteritis is a common condition that causes vomiting or diarrhoea. It's sometimes called 'stomach flu' or a 'vomiting bug'. Gastroenteritis means inflammation of the stomach and intestine, and usually describes an infection of the gut.

by Dr Doug McKechnie, MRCGP

Digestive health

Appendicitis

Appendicitis is inflammation of the appendix, a small pouch on the gut wall connected to the large intestine. It is a medical emergency as, left untreated, the appendix can burst or perforate.

by Dr Colin Tidy, MRCGP

Lactose intolerance

According to GP Dr Mehta, certain viruses and parasites, such as giardia, can also lead to lactase deficiency in up to 40% of infected people. This means that temporarily injury to the gut lining reduces the amount of lactase your body produces - an enzyme which helps you digest lactose².

As a result, gastroenteritis is the most common cause of temporary lactose intolerance - also called secondary lactose intolerance - which lasts until the gut has fully repaired itself. For several weeks, this could mean that eating milk and dairy products causes you discomfort and symptoms such as diarrhoea and flatulence (wind).

Other food sensitivities

Gastroenterologist Dr Albu-Soda adds that gastroenteritis can also trigger other food sensitivities: "This disturbance may cause problems with the movement of the gut and could make the gut more sensitive to food. Infections may also trigger some immune system changes that encourage the body to react to previously harmless components of food."

One 2021 study found that a bout of gastroenteritis could affect someone's ability to tolerate foods that contain gluten, milk, soy, or wheat³. This can be either temporary or permanent.

Inflammatory bowel disease (IBD)

Research has also indicated a link between gastroenteritis and developing inflammatory bowel disease (IBD), although this is much more rare than post-infectious IBS. Pharmacist Kanani explains:

"Conditions such as ulcerative colitis and Crohn’s disease fall under the category of IBD, and they are characterised by chronic inflammation of the digestive system. This can cause symptoms such as changes to stool (poo) habits, abdominal pain, weight loss, and fatigue. It can affect daily activities, performance in school, the ability to work, and a patient's social life."

The gastroenteritis bacteria and viruses most likely to cause IBD are non-typhoidal salmonella, campylobacter, and clostridium, all of which we can get from eating contaminated food. For this reason, storing, preparing, and cooking food in a way that kills harmful germs is important for both our short and long-term health.

Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is a rare autoimmune disease where your immune system mistakenly attacks your own nerves as well as foreign cells, during an infection. Although it's a very uncommon complication of gastroenteritis, it's thought that two-thirds of people with GBS experienced gastroenteritis weeks before developing this disease⁴.

Dr Mehta adds that your risk of developing GBS during the two months following gastroenteritis increases if you were infected with the bacteria campylobacter. You're most likely to get a campylobacter infection through food poisoning or by drinking contaminated water.

Always wash your hands after handling raw chicken, meat, and seafood, and make sure that these foods aren't undercooked.

Further reading

1. IFFGD: Post Infectious IBS.

2. Kliegman: Lactase deficiency.

3. Aguilera-Lizarraga et al: Local immune response to food antigens drives meal-induced abdominal pain.

4. BMJ: Guillain-Barre syndrome.