It’s never fun to get sick, but it’s especially awful to feel under the weather when you’re on vacation. Unfortunately, it’s not uncommon. The stress of travel, coupled with jet lag, can tax your immune system and make you more susceptible to colds and other respiratory illnesses. A high level of physical activity can put you at risk for sprains, strains and other injuries. Experiences like going on a boat on choppy waters, riding a bus on winding roads and hiking or skiing at high altitudes can cause symptoms like stomach upset, dizziness and headaches. And if you unwittingly dine on food that contains bacteria, viruses or parasites, you can develop a food-borne infection.

With domestic travel, you’re vulnerable to diseases that are endemic to the area you’re visiting, says Dr. Lin H. Chen, director of the Harvard-affiliated Travel Medicine Center in Cambridge, Massachusetts, and president-elect of the International Society of Travel Medicine. We’re talking tick-borne illnesses like Lyme disease in the Northeast and fungal infections such as Valley fever (caused by the Coccidioidomycosis fungus) in the Southwest. Serious airborne viruses like measles, which has made a resurgence in New York state and other areas of the country, can make you sick too, if you haven’t been vaccinated or had measles before.

When you travel outside the country, the biggest threat is traveler’s diarrhea, due to exposure to different germs and bacterial strains in the food and water. Research indicates that between 6 and 87 percent of people get sick when journeying far from home; traveler’s diarrhea affects more than half of people traveling to northern Africa, Latin America, the Middle East and Southeast Asia. Respiratory infections and mosquito or tick bites, rashes and fevers are also common.

Prevention is the best medicine, and it starts with getting any needed vaccinations before traveling, washing your hands well and often, and taking motion sickness remedies if you’re prone to queasiness. But if you do fall ill during a trip, there are strategies you can rely on. Here’s advice to minimize the amount of time you spend out of commission once your Out of Office reply is turned on.

Turn to your first aid kit

It’s a good idea to be prepared for a cold, headache and muscle aches and pains by tucking some familiar remedies in your suitcase. Start with acetaminophen (Tylenol) or ibuprofen (Advil), an anti-diarrheal like loperamide (Imodium A-D) or bismuth subsalicylate (Pepto-Bismol), and an antacid like Tums, which contains calcium carbonate. If you have seasonal allergies, you’ll want to bring along a newer-generation antihistamine (Allegra, Claritin, Zyrtec or Xyzal); you can also use a topical form of the older antihistamine diphenhydramine (Benadryl) to calm down an allergic skin reaction, bug bites or poison ivy.

Your first aid kit should also include bandages, a topical antibiotic and hydrocortisone if you’re going somewhere isolated. “The more remote and the farther away from a city, the bigger your first aid kit should be,” says Chen.

Drink lots of clear fluids

Air travel can be dehydrating, so drink plenty of fluids while in flight. If you get traveler’s diarrhea, which can dehydrate you quickly and to a dangerous degree, be sure to “drink more water than you usually do,” advises Teri Dreher, a registered nurse and patient advocate for NShore in Chicago.

If your gastrointestinal issues are severe, supplement your water with sports/electrolyte drinks like Gatorade or Pedialyte, which can be found at most pharmacies and convenience stores, or broth. In these instances, “it’s important to replace the lost salts in your body,” says Dr. Dheeraj Taranath, regional medical director at MedExpress Urgent Care in Reading, Pennsylvania.

Relax

Most illnesses won’t require a doctor’s care. Unless you have a fever (a sure sign of infection), just take it easy. “Adjust your itinerary to allow more time for additional rest,” Taranath says. “Don’t be afraid to take a day to recuperate in your hotel room.” Relax in a warm shower or bath, drink hot tea and nap until you feel better.

If you’re well enough to leave your room, take advantage of your destination without overexerting yourself: Save walking across a city for when you’re feeling better, and take a guided tour on a bus or boat or see a local show instead. “Listen to your body and take a break when you get tired,” advises Chen.

Stick to a bland diet

If you’re having stomach problems, refrain from eating difficult-to-digest foods like fatty meats, greasy or spicy foods, citrus fruits, dairy products and alcohol, which can irritate the GI tract. Stick to the BRAT diet: bananas, rice (white), applesauce and toast for 24 hours, and then slowly resume a more balanced diet.

Take probiotics

Probiotic supplements, available at drugstores and supermarkets, help your gut combat potentially harmful bacteria that you might encounter when traveling. “Double up on your probiotics if you get sick,” Dreher says, to limit the duration and severity of your illness. She also recommends beginning a course of probiotics two weeks before you travel to increase your resistance to germs. This is a somewhat controversial strategy, but there’s research to support the use of probiotics: An analysis of 12 studies, for instance, found that probiotics containing Saccharomyces boulardii or a mixture of Lactobacillus acidophilus and Bifidobacterium bifidum can be safe and effective in preventing traveler’s diarrhea. Reputable probiotic brands for digestive health, according to Consumer Lab, include Align, Culturelle, MegaFood MegaFlora, Renew Life Ultimate Flora and Vita Miracle Ultra 30.

Start medicating at home

If you get food poisoning or traveler’s diarrhea and develop a fever, start taking Imodium or Pepto-Bismol. If you’re really sick, take an antibiotic — you can ask your doctor for a “just in case” antibiotic prior to leaving the country. If you haven’t brought one with you, go to a local clinic for a prescription. In some countries, you can even buy ciprofloxacin (Cipro) or other antibiotics over the counter at drugstores. In one study, ciprofloxacin reduced sick time from 81 hours to 29 hours.

If you experience symptoms including headaches, nausea, lightheadedness and disrupted sleep when you travel to high-altitude destinations — 8,000 feet above sea level or higher — consider asking your doctor about preventive treatments for altitude sickness. Depending on the severity of your symptoms and how much they interfere with your ability to enjoy your vacation, a doctor might prescribe a short course of medication to speed up the process of acclimating to the oxygen-thin air. The most commonly used drug for altitude sickness is called acetazolamide. If your symptoms are more minor, you might be advised just to take Ibuprofen and hydrate.

Go to urgent care

If you’re really sick with a cold or flu, call your health insurance provider to help you find an urgent care center. “For non-life-threatening issues, urgent care facilities offer convenient, extended hours and shorter waits,” Taranath says, compared to emergency rooms.

Go to an ER

If you experience symptoms such as progressive weakness or signs of a stroke or heart attack (shortness of breath, chest pain), seek medical attention immediately. Likewise, if you develop a fever while you’re traveling in a developing country, such as after swimming in a river or petting a wild animal, or are in a region with known outbreaks of infections like Ebola, see a doctor sooner rather than later. “Fever is one of the signs of a serious infection like malaria,” says Chen, “and it can progress rapidly and be life-threatening.” Also head to an ER if you’ve been sick for a few days and aren’t getting better, or if you sprain an ankle or knee and can’t walk without pain.

“When in doubt, do the responsible thing and go to the hospital,” agrees Dreher. Start with a call to your health insurance provider for preapproval, if possible, but don’t delay treatment based on financial fears. “Even if you don’t have travelers insurance, the cost for treatment may not be a big deal,” she says. “Many European nations have socialized medical care, for instance. The bill for a two- to three-day hospital stay may be a couple hundred dollars, not several thousand.”

Always travel with a photocopy of the information page from your passport, your medications in their original bottles and one sheet of paper listing your medications, surgeries, allergies and doctors’ contact information. You’ll need to provide as much medical information to the hospital as possible if you’re admitted.

Be aware of your patient rights. “No matter where you are, you’re entitled to be treated by someone who speaks your language,” Dreher says. You can also refuse medical advice. “If you feel you’re being price-gouged, respectfully decline treatment,” she adds. “If you’re starting to feel better, be polite and say, ‘We’re going to go home now.’ It’s your right to leave if the doctor or staff is doing something that makes you uncomfortable.”

Go home

Travelers insurance can help get you home in case of a medical emergency. “I recommend that travelers consider purchasing travel insurance, especially if they’re going to an exotic location, but I don’t push it on people,” says Chen. “We all have different levels of tolerance for potential problems depending on our health status.” There are also different levels of insurance you can purchase, from coverage for lost luggage and flight delays all the way up to medical insurance and medical evacuation insurance, which can be required if you’re mountain climbing.

“Some policies can grease the wheels to get you back quickly,” Dreher says. But don’t travel if you’re more than moderately sick — and be aware that some airlines refuse to allow people who are noticeably ill to board a plane. “People do not do well on planes when they’re seriously ill,” Dreher says. “Altitude makes a moderately sick person sicker. Get well enough to travel before you fly.”

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