Gastroenteritis: home care and when to see a doctor

A common and highly contagious infection

Gastroenteritis, often called "stomach flu", is an infection of the stomach and intestines: diarrhoea, vomiting, stomach cramps, sometimes fever. It is usually caused by a virus: norovirus can affect anyone, rotavirus mainly young children. Less often, a bacterium passed on through food is the cause.

It usually gets better on its own. Vomiting generally stops within 12 to 48 hours. In young children, diarrhoea often lasts 5 to 7 days and usually stops within 2 weeks.

Norovirus passes easily from person to person: through hands, surfaces, objects, food or vomit. Symptoms start 12 to 48 hours after infection. You are most contagious while you are ill, but the virus can stay in your stools for up to 2 weeks and survive 2 to 3 weeks in the environment (Sciensano). So it spreads easily in families, nurseries, care facilities or at work, in Brussels as elsewhere.

The key point: preventing dehydration

The main risk is losing too much water and minerals (salts). Babies, young children, older people and people with a long-term condition such as diabetes are the most vulnerable.

For a healthy adult who is losing little fluid, drinking small amounts of water or broth often may be enough. If losses are large, or for someone at risk, use an oral rehydration solution (ORS): a precise mix of sugars and salts, sold in sachets at the pharmacy, to be dissolved in the amount of water shown on the pack.

In children: small amounts, often

• Give the ORS in small sips, with a spoon, a syringe or a bottle, every few minutes.
• After each watery stool or each episode of vomiting, the CBIP advises about 60 to 120 ml if the child weighs less than 10 kg, and 120 to 240 ml if they weigh more than 10 kg.
• If your child vomits, do not stop: carry on more slowly.
• Keep breastfeeding on demand, and give the usual formula without changing it.
• As soon as your child is hungry, offer their usual meals in small portions: there is no need to stop food or follow a special diet.

What to avoid

• Fizzy drinks, cola, fruit juice and energy drinks to rehydrate a child: they do not replace ORS.
• Loperamide in children (a medicine that slows down the bowel): contraindicated under 2 years, not recommended under 6 years. Never without medical advice.
• Ibuprofen and other anti-inflammatories in a child who is vomiting or has diarrhoea: combined with dehydration, they increase the risk of acute kidney injury. Fever does not always need treating; if it bothers your child, choose paracetamol (see our fever page).
• Anti-sickness medicines (metoclopramide, domperidone): according to the CBIP, their risks outweigh their benefits, especially under 12 years.
• Antibiotics "just in case": they do not work against viruses. The doctor keeps them for specific situations, such as blood in the stools with fever, or a weakened immune system.

In adults: which medicines?

Rehydration remains the basis of treatment. According to the CBIP (Belgian Centre for Pharmacotherapeutic Information):

• loperamide can ease diarrhoea, but not if you have a fever with bloody or mucus-filled stools; it can cause constipation;
• racecadotril can reduce the number of stools, but its role is very limited;
• the effectiveness of probiotics has not been clearly shown;
• paracetamol relieves fever or pain and is generally well tolerated.

Do you take long-term treatment (water tablets, medicine for blood pressure or diabetes, anti-inflammatories…) and are you dehydrated? Call your doctor to find out whether it should be adjusted for a few days. Do not stop anything on your own.

Recognising dehydration

• dry mouth and tongue;
• little or no urine (in babies, fewer wet nappies);
• sunken eyes;
• unusual drowsiness, a floppy child or, on the contrary, a very irritable one;
• signs of severity: fast breathing, cold hands and feet, pale or mottled skin.

When to see a doctor quickly

Contact your GP the same day if:

• the patient is a baby under 6 months;
• you notice signs of dehydration;
• vomiting keeps coming back and fluids do not stay down, the child refuses to drink, or the vomit is green;
• there is blood or mucus in the stools;
• the fever is high (in children: 38 °C or more under 3 months, 39 °C or more after that);
• stomach pain is severe or in one place, or the belly is swollen;
• the person is elderly, frail, has a long-term condition or a weakened immune system;
• diarrhoea has not improved after 7 days, or it started after a trip abroad.

Call 112 in case of marked drowsiness or difficulty waking up, pale or mottled skin with cold hands and feet, difficulty breathing, a stiff neck or spots on the skin that do not fade when pressed. Outside opening hours, call the doctor on duty on 1733. See also our emergencies page.

Hygiene: limiting the spread

• Wash your hands with soap and water after using the toilet, after changing a nappy, and before cooking or eating. Against norovirus, soap works better than alcohol hand gel, which does not replace handwashing.
• Use one towel per person.
• Clean, then disinfect the toilet and soiled surfaces, for example with bleach diluted according to the label.
• Wash soiled laundry at 90 °C, or twice at 70 °C.
• The sick person should not prepare meals for others.

Returning to school, nursery or work

Stay at home as long as you have symptoms. A child goes back to nursery or school no sooner than 48 hours after the last episode of diarrhoea or vomiting, also following the rules of the nursery or school. No swimming pools for 2 weeks after the last episode of diarrhoea.

Do you work with food (kitchen, restaurant, food shop)? Tell your employer and wait at least 48 hours after your symptoms have stopped before going back to work. If you work in healthcare or with young children, ask your employer or the occupational health doctor for advice.

The rotavirus vaccine

In Belgium, the Superior Health Council recommends vaccinating all babies against rotavirus. The vaccine is given by mouth, in 2 or 3 doses depending on the vaccine: at 8 and 12 weeks, and for one of the vaccines at 16 weeks. Vaccination must be completed before 6 months of age. It effectively prevents severe forms and reduces hospital admissions. A very rare but serious side effect is possible: intussusception (part of the bowel folding into itself), mainly in the weeks after the first dose.

At Maison Médicale Parc Astrid

In Anderlecht, our team can advise you in French, Dutch, English and Turkish. If an older or frail person is struggling to drink, call us: the doctor will assess the situation and, if needed, our nursing team can provide follow-up at home.

Sources

• CBIP – Belgian Drug Formulary, 3.4 Antiemetics and 3.6 Antidiarrhoeals (2026)
• CBIP – Belgian Drug Formulary, 8.1 Fever and pain (2026)
• CBIP – Belgian Drug Formulary, 12.1.1.11 Rotavirus vaccine (2026)
• Sciensano – Norovirus fact sheet for the public (2016)
• ESPGHAN/ESPID – Guidelines for the management of acute gastroenteritis in children in Europe (2014)
• NICE – CG84 Diarrhoea and vomiting caused by gastroenteritis in under 5s (2009)
• CDC – Norovirus Fact Sheet for Food Workers (2024)