You planned beaches, waterfalls and churrasco, not a day locked in your hotel bathroom. If you have travelers' diarrhea in Brazil, you are far from alone: the CDC calls it the most predictable travel-related illness. The good news is that most cases pass in a few days. This guide shows what genuinely helps, what to ask for at the pharmacy, which signs mean you need a doctor, and how to be assessed in English without leaving your room.

Quick answer: drink fluids little and often, use oral rehydration salts if losses are heavy, rest, and watch for warning signs. Antibiotics are sold in Brazil only with a prescription. If symptoms are distressing or stop you from following your plans, book an online consultation in English.

What travelers' diarrhea is

Travelers' diarrhea is a set of symptoms, mainly loose stools, cramps and urgency, caused by different germs in food or water. According to the CDC Yellow Book 2026, bacteria cause most cases, viruses cause a smaller share (more often with vomiting), and parasites are less common and tend to appear later in longer trips. The CDC also notes that careful eaters can still get ill, because restaurant hygiene is often outside a traveler's control. In other words: it is not your fault, and it does not mean you did something wrong.

How long it usually lasts

  • Toxin-related "food poisoning": usually resolves within 12 to 24 hours;
  • Viral diarrhea: generally 2 to 3 days;
  • Bacterial diarrhea, untreated: usually 3 to 7 days;
  • Parasitic diarrhea: can persist for weeks without treatment.

Source: CDC chapter on travelers' diarrhea.

What helps right now

1. Replace fluids, little and often

Replacing fluids is the key step and helps you feel better sooner. For mild cases, any drink you tolerate works; very sugary drinks such as sodas can make diarrhea worse if taken in quantity. For heavier losses, use oral rehydration salts mixed with safe water as the packet instructs (rehydration guidance). Take small sips if you feel sick (self-care advice). The World Health Organization notes that oral rehydration solution is a cheap, effective way to replace lost fluids.

2. Eat when you feel able to

You do not have to fast. Eat when you feel able to; it may help to avoid fatty or spicy food for a while (NHS guidance).

3. Wash your hands and protect your companions

Wash your hands with soap often, do not share towels or cutlery, and clean toilet surfaces. When soap is not available, an alcohol hand sanitiser of at least 60% helps before eating.

What to ask for at a Brazilian pharmacy

  • "Sais de reidratação oral" or "soro de reidratação oral" – oral rehydration salts;
  • "Estou com diarreia" – I have diarrhea;
  • "Precisa de receita?" – Does it need a prescription?

Tell the pharmacist about your allergies, other medicines, pregnancy or chronic conditions. Anti-diarrheal medicines that slow the bowel can relieve symptoms, but the CDC advises that they should not be used alone when there is blood in the stool or fever, and the NHS advises not to give them to children under 12. Need a 24-hour option? See how to find a 24-hour pharmacy in Brazil.

Antibiotics: why the pharmacy will ask for a prescription

For mild diarrhea, the CDC does not recommend antibiotics. In moderate or severe cases a doctor may consider them, weighing benefits against side effects and antimicrobial resistance. In Brazil, antibiotics are dispensed only with a prescription, which the pharmacy retains, valid for 10 days (antimicrobial dispensing rules; current list and validity). Do not take leftover antibiotics or tablets recommended by friends: whether you need one, and which, depends on an individual assessment.

When to see a doctor

  • diarrhea that is distressing or stops you from following your plans;
  • blood in the stool, or fever;
  • vomiting that stops you keeping fluids down;
  • signs of dehydration, such as dark, strong-smelling urine or peeing much less than usual;
  • diarrhea for more than 7 days or vomiting for more than 2 days;
  • pregnancy, older age, a weakened immune system or a chronic condition;
  • a baby or young child with symptoms: children dehydrate faster.

Sources: NHS, CDC.

How an online consultation with PresençaMed International works

  1. Book and pay on the website: choose a time on the booking page. One price per consultation: US$ 50, by card (international cards accepted) or Pix. No CPF needed; your passport details are enough.
  2. At the time you chose, the doctor contacts you on WhatsApp and starts the video call.
  3. The consultation is in English or Spanish, every day from 8am to 10pm Brazil time (GMT-3), with a physician registered with the CRM.
  4. If the doctor considers it appropriate, prescriptions and documents are sent by e-mail. Most prescriptions are digital, including Brazil's blue (B1) and yellow (A) forms — PresençaMed already issues them digitally. B2 prescriptions are not issued.

A prescription is never guaranteed in advance: it always depends on the doctor's assessment, and sometimes the right recommendation is an in-person examination. Questions before booking? Use the form on our frequently asked questions page (please do not include clinical details there; health data is shared only in the consultation, under medical confidentiality and Brazil's data protection law).

Telehealth is authorised throughout Brazil, and the physician may always decide that in-person care is needed (Brazilian telehealth law). See also what to do in a medical emergency in Brazil and whether travel insurance covers an online doctor in Brazil.

Emergency signs: go now, do not wait

  • vomiting blood, or vomit that looks like coffee grounds;
  • sudden, severe abdominal pain;
  • confusion, extreme drowsiness or fainting;
  • severe difficulty breathing;
  • pale, grey or blotchy skin or lips.

Call 192 (SAMU), the public emergency ambulance service, or go to the nearest emergency room or UPA 24h urgent care unit.

Frequently asked questions about travelers' diarrhea in Brazil

Is travelers' diarrhea common in Brazil?

Travelers' diarrhea is common worldwide among international travelers; the CDC reports rates of 30% to 70% over two weeks depending on destination and season.

Can I buy antibiotics for diarrhea without a prescription?

No. In Brazil the pharmacy must retain a prescription, valid for 10 days.

Do probiotics prevent it?

According to the CDC, current data are insufficient to recommend probiotics for prevention.

Can an online consultation help?

Often, when there are no emergency signs. The doctor assesses you by video and decides whether online care is enough or you should be examined in person.

Do not lose more days of your trip: book an online consultation

Book your online consultation with a physician registered with the CRM, in English or Spanish, by video, every day from 8am to 10pm Brazil time. US$ 50 per consultation. Any prescription, certificate or report depends on the doctor's assessment.

Medical review: Dr. Marcelo R. Luján, Physician, CRM-SC 42.900, postgraduate in Family and Community Medicine (UNIFESP). Technical director of PresençaMed (Lujan e Perazolo Pera Serviços Médicos LTDA, CRM-SC PJ 14623). This content is general information and does not replace an individual consultation. Intense symptoms, or symptoms that worsen quickly, require in-person care or an emergency service (call 192, SAMU).