Food poisoning: what to do

Most food poisoning on a trip is mild and gets better on its own within a few days. The most important thing you can do is replace the fluid you lose, ideally with oral rehydration solution (ORS). Rest, sip fluids often, and eat when you feel able.

Get medical help quickly if you have a fever of 38°C (100.4°F) or higher, blood or mucus in your stool, severe stomach pain, signs of dehydration, or if you cannot keep fluids down. Babies, young children, pregnant travelers, older people, and people with long-term health conditions should get advice earlier.

Food poisoning or travelers’ diarrhea?

For most travelers, these are the same problem: an infection or a toxin picked up from contaminated food or water. TravelHealthPro, the UK’s national travel health service, defines travelers’ diarrhea as three or more loose stools in 24 hours, often with cramps, nausea, vomiting, or fever.

Common symptoms include:

• diarrhea
• feeling sick or vomiting
• stomach cramps or pain
• a high temperature
• feeling generally unwell

When it starts. The NHS says symptoms usually start within a few hours to a few days after eating contaminated food, but can sometimes take a few weeks. So the last meal you ate is not always the cause. When the illness comes from toxins already in the food, the CDC says vomiting and diarrhea usually settle within 12 to 24 hours. Parasites such as Giardia usually take one to two weeks to cause symptoms.

How long it lasts. Without treatment, the CDC says bacterial diarrhea usually lasts 3 to 7 days and viral diarrhea 2 to 3 days. The NHS says diarrhea usually stops within 5 to 7 days and vomiting within 1 or 2 days.

Is it an allergic reaction instead? Swelling of the throat or tongue, trouble breathing or swallowing, or feeling faint within minutes of eating are signs of anaphylaxis, a severe allergic reaction, according to the NHS. That is an emergency: use an adrenaline auto-injector if you have one and call the local emergency number. Our guide to eating out abroad with a food allergy explains how to prepare.

What to do in the first 24 hours

1. Drink fluids often. Take small sips if you feel sick. Use safe water: sealed bottled, boiled, or treated. Our guide to tap water and ice explains how to make water safe.
2. Use oral rehydration solution if you are losing a lot of fluid. ORS packets contain the right mix of sugar and salts to replace what your body loses. The CDC says to mix one packet with the amount of boiled or treated water shown on the pack. For mild cases, the CDC says other drinks, including sports drinks, are fine.
3. No ORS packets? TravelHealthPro gives a backup recipe: six level teaspoons of sugar and half a teaspoon of salt in one liter of safe water. Switch to proper ORS packets when you can.
4. Avoid fruit juice and fizzy drinks. The NHS says they can make diarrhea worse.
5. Eat when you feel able. The NHS suggests avoiding fatty or spicy food at first.
6. Rest, and keep breastfeeding or bottle feeding babies as usual.

Stomach bugs can spread to the people you travel with. The NHS advises washing your hands with soap and water often, not preparing food for others if possible, not sharing towels or cutlery, and not using a swimming pool until at least 48 hours after your symptoms stop.

Medicines: ask a pharmacist or doctor first

Check with a pharmacist or doctor before taking any medicine, especially for children or during pregnancy.

• Loperamide reduces how often you need the toilet, which can help on a long journey. TravelHealthPro says it is for adults and children over 12, and not for people with a high fever, severe stomach pain, or blood or mucus in their stool.
• Bismuth subsalicylate can help with mild diarrhea, but it is not for everyone. The CDC says to avoid it during pregnancy, if you are allergic to aspirin, or if you take blood thinners, and it is generally not recommended for children.
• Antibiotics are usually not needed for mild travelers’ diarrhea. For more severe illness, a doctor may prescribe one. The right antibiotic depends on where you are, because resistance differs between regions.

Red-flag symptoms: when to get medical help

The NHS says to get emergency help right away (call the local emergency number or go to an emergency department) if you or your child:

• vomit blood, or vomit that looks like ground coffee
• have green vomit (or yellow-green vomit in a child)
• have a sudden, severe stomach ache or headache
• have a stiff neck and pain when looking at bright lights
• have blue, gray, pale, or blotchy skin, lips, or tongue
• have severe difficulty breathing, or are taking lots of quick, short breaths
• are confused or not responding as usual

See a doctor right away if:

• you have a fever of 38°C (100.4°F) or higher
• there is blood or mucus in your stool
• you keep vomiting and cannot keep fluids down
• you have yellow skin or eyes (jaundice), a rash, or other worrying symptoms
• you still have signs of dehydration after using oral rehydration solution
• you are worried about a baby under 12 months, or a child stops feeding or has fewer wet diapers

Book a doctor’s visit if:

• your symptoms do not improve within three days
• diarrhea lasts more than 7 days, or vomiting more than 2 days
• diarrhea lasts more than two weeks, even after you get home. Tell the doctor where you traveled, because the CDC notes that diarrhea lasting this long can point to parasites, which need specific treatment.

Signs of dehydration

The NHS lists these signs in adults and children:

• feeling thirsty
• dark yellow, strong-smelling pee, or peeing less often than usual
• feeling dizzy, lightheaded, or tired
• a dry mouth, lips, and tongue
• sunken eyes

In babies, also watch for a sunken soft spot on the top of the head, few or no tears when crying, fewer wet diapers, and being drowsy or irritable.

Babies, children, pregnancy, and older travelers

Babies and children can become dehydrated quickly. The CDC says rehydration is the main treatment and should start early. Keep breastfeeding on demand, and bottle-fed babies can keep drinking their formula. The NHS says not to give medicine to stop diarrhea to children under 12, and not to give aspirin to children under 16.

Pregnant travelers should rehydrate quickly; the CDC calls this the treatment of choice. Avoid bismuth subsalicylate. If antibiotics are needed, a doctor can choose one that is suitable in pregnancy. The CDC also warns that hepatitis E, which spreads by the fecal-oral route, is more likely to cause severe illness in pregnancy. Do not drink water treated with iodine. Get medical attention right away for any pregnancy warning signs.

Older travelers and people with health conditions are more affected by dehydration. TravelHealthPro advises getting medical advice early if they cannot keep fluids down or show signs of dehydration. It also says people with a weak immune system, inflammatory bowel disease, or chronic kidney or heart disease should take particular care.

Getting medical care abroad

• In an emergency, call the local emergency number. The European Commission says 112 works free of charge everywhere in the EU, and in some other countries, including Switzerland. Look up the number for your destination before you travel.
• For non-urgent help, a pharmacist is a good first stop. Your travel insurer’s 24-hour assistance line and your hotel can also help you find a doctor, and your country’s embassy or consulate may be able to help too.
• Plan to pay upfront. The CDC advises keeping your bills and invoices so you can claim from your insurer later. Treatment abroad can be expensive: the UK government gives the example of a stomach bug or infection treated in a US hospital, with possible medical evacuation, costing £150,000 or more.
• Buy medicines from a proper pharmacy, not from markets or street sellers. The CDC cites a WHO estimate that 10% of medical products in low- and middle-income countries are substandard or falsified.

Once you feel better, our guide on how to avoid food poisoning when traveling can help you lower the risk for the rest of your trip.