Food poisoning: Treatment, symptoms, and causes

Gastroenteritis is a condition involving inflammation of the lining of the gut – in particular, of the stomach and intestines. It generally resolves without medication, but, in some cases, it can lead to complications.

Food poisoning is a major cause of gastroenteritis, resulting in a well-known set of unpleasant symptoms.

Gastroenteritis is usually caused by viruses, bacteria, or parasites; when the source of such infection is contaminated food, it is called food poisoning. Gastroenteritis may also be referred to as “gastric flu” or “stomach flu.”

Fast facts on gastroenteritis and food poisoning

Here are some key points about food poisoning and gastroenteritis. More detail and supporting information is in the body of this article.

Most cases of gastroenteritis are caused by infection with bacteria, viruses, or parasites

Diarrhea, nausea, vomiting, and abdominal pain are typical symptoms of gastroenteritis

Gastroenteritis is usually self-limiting, and tests are not usually necessary for a diagnosis

The most serious complication of food poisoning and gastroenteritis is dehydration, especially for vulnerable people such as the very young and very old


Drinking water
Drinking plenty of liquids can help treat dehydration.

Gastroenteritis and food poisoning usually resolve themselves without any medical intervention. Treatment is focused on reducing the symptoms and preventing complications, especially dehydration.

The main treatment and prevention strategy for food poisoning is to rest and replace lost fluids and electrolytes by:

Drinking plenty of liquids (preferably with oral rehydration salts to replace lost electrolytes – see below)

Ensuring fluid intake even if vomiting persists, by sipping small amounts of water or allowing ice cubes to melt in the mouth.

Gradually starting to eat again. No specific restrictions are recommended, but blander foods might be easier to start with (cereal, rice, toast, and bananas are good examples).

The following may worsen symptoms during gastroenteritis episodes: fatty, sugary, or spicy foods, dairy products, caffeine, and alcohol.

To avoid the dangerous and potentially fatal effects of dehydration from diarrhea, oral rehydration salts (ORS) are recommended for vulnerable people (for example, infants and children, adults over 65 years of age, and people with weakened immunity).

Use of ORS in developing countries has been “one of the great public health success stories of our time,” according to a former director-general of the World Health Organization (WHO), Dr. Gro Harlem Brundtland – it reduced the number of deaths every year among children with acute diarrhea, from 5 million to 1.3 million deaths.

In developed countries, while the threat of death is smaller, rehydration is nonetheless important.

Salt, glucose, and minerals lost through dehydration are replaced by sachets of oral rehydration salts available from pharmacies and online. The salts are dissolved in drinking water and do not require a doctor’s prescription.

It is important to get the right concentration, as too much sugar can make diarrhea worse, while too much salt can be extremely harmful, especially for children. A more dilute solution (for instance using more than 1 liter of water), is preferable to a more concentrated solution.

Store-bought products like Pedialyte and Gatorade also help restore electrolytes and increase hydration.

Drug treatments for gastroenteritis

Drugs are available to reduce the main symptoms of gastroenteritis – diarrhea and vomiting:

Antidiarrheal medication such as loperamide (branded versions include Imodium, and Imotil, among others) and bismuth subsalicylate (for example, Pepto-Bismol)

Antiemetic (anti-vomiting) medication such as chlorpromazine and metoclopramide

Antidiarrheals are available OTC, while the antiemetics are available from doctors

Talk to a doctor before taking anti-diarrhea medication as some infections may get worse with anti-diarrhea medicines.

Probiotics and gastroenteritis

Probiotics (live “good” bacteria and yeasts) may also be helpful in treating gastroenteritis, according to some newer research. One study found that the use of probiotics in children hospitalized for acute gastroenteritis shortened their hospital stay by an average of 1.12 days.

Specifically, there is some evidence to support the use of the following strains of beneficial bacteria in the treatment of gastroenteritis in children, alongside the use of oral rehydration solutions without dietary restriction:

Lactobacillus rhamnosus GG

Saccharomyces boulardii

This is a new area of study, so there may be more research about using probiotics to treat gastroenteritis in the future.


Man with stomach pain holding his abdomen.
Abdominal cramps can be a symptom of gastroenteritis.

Four well-known, classic symptoms are typical of gastroenteritis:

Diarrhea (loose stools)

Nausea (feeling sick or queasy)


Abdominal pain (‘stomach cramps’)

These symptoms can occur in any combination; they generally have a sudden (acute) onset, but this, and symptom severity, can vary.

The onset of symptoms after eating contaminated food can be within a few hours, but the incubation period can also be much longer, depending on the pathogen involved.

Vomiting usually happens earlier on in the disease, diarrhea usually lasts for a few days, but can be longer depending on the organism that is causing the symptoms.

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