Travel wellness starts with the basics, not a suitcase of supplements

Key takeaways

• CDC’s 2026 Yellow Book says 30% to 70% of travelers get travelers’ diarrhea over a two-week trip, depending on where and when they go, and careful food rules don’t guarantee protection¹.
• A 2007 World Health Organization study found that sitting four hours or more in a plane, car, bus or train roughly doubles the risk of a blood clot, though the absolute risk stays low, about 1 in 6,000³.
• CDC rates the evidence for ginger against motion sickness as weak and contradictory, and lab trials found acupressure wristbands worked no better than placebo⁸.
• Medicine rules change at the border: the State Department warns that Adderall is illegal in Japan, and melatonin, a store-shelf supplement in the U.S., is a prescription-only medicine in the UK¹¹¹².
• Two doses of the MMR vaccine are about 97% effective against measles, and CDC says most unvaccinated travelers who bring measles into the U.S. are Americans¹⁴.

The most predictable illness in travel medicine isn’t exotic. It’s diarrhea. Over a two-week trip, 30% to 70% of travelers come down with it, depending on the destination and the season, according to CDC’s 2026 Yellow Book, the agency’s guide for travel clinicians¹.

Yet the travel aisle sells something else: protection from the germs on the plane. In 2008, the makers of Airborne, a fizzy tablet marketed to protect people from colds in crowded places like airplanes, settled Federal Trade Commission charges². The FTC said there was “no competent and reliable scientific evidence” behind its cold claims, and settlements totaled about $30 million².

The risks that show up on trips are ordinary: stomach bugs, stiff legs on long rides, dry cabin air, sunburn, jet lag, motion sickness and medicine rules at the border.

Most are handled by the same basics you rely on at home: clean hands, movement, light, sleep, sun sense and planning. This guide covers what works, what doesn’t, and what to pack.

Stomach bugs are the trip’s most likely illness

Many travelers know the old rule: “boil it, cook it, peel it, or forget it.” It’s sensible, but CDC says it’s no guarantee. People who follow it still get sick, and poor restaurant hygiene and weak sanitation likely drive most of the risk¹. Studies of counseling travelers on food and water habits found it may not lower their odds¹.

What you can control is your hands. Wash with soap before eating, and use a sanitizer with at least 60% alcohol when soap isn’t available¹.

Bismuth subsalicylate, the pink stomach remedy, cut cases by about half in studies from Mexico¹. Few travelers take it to prevent illness because the dosing takes a lot of tablets¹. It can turn the tongue and stool black, and it can cause constipation or nausea¹.

It isn’t for everyone. CDC lists people to avoid it, including anyone allergic to aspirin, with gout or kidney problems, or taking blood thinners or methotrexate¹. It’s not generally recommended for children under 12 or during pregnancy¹.

Probiotics are popular with natural-health travelers, but CDC says the studies are small and products vary, so there isn’t enough data to recommend them¹. Antibiotics to prevent diarrhea aren’t recommended for most travelers either¹.

If you do get sick, fluids come first. Use sealed or treated drinks, and oral rehydration salts for heavy losses, since sugary soda can make diarrhea worse¹. Get medical care for blood in the stool, fever, severe illness or diarrhea that lasts more than two weeks, and watch young children closely because they dehydrate faster¹.

Long rides raise clot risk, in cars as well as planes

In 2007, a World Health Organization research project called WRIGHT reported that travel of four hours or more roughly doubles the risk of venous thromboembolism, a blood clot in a deep vein that can travel to the lungs³. The absolute risk stayed low, about 1 in 6,000³. CDC’s 2026 Yellow Book is more cautious about the size of the jump: it says long flights might raise clot risk two- to fourfold, but that the studies don’t agree, and that flights under four hours add almost no risk⁴.

Two findings surprise many people. The risk applied to cars, buses and trains, not just planes, and it stayed raised for about four weeks after the trip³. Taking several flights close together added to it³.

CDC’s 2026 guide adds that most travel-related clots happen in people who already have a risk factor⁴. These include:

• active cancer, estrogen use or pregnancy;
• recent surgery, injury or hospital stay;
• obesity, age over 40, or a past clot or family history;
• being very short (under 5 feet 3 inches) or very tall (over 6 feet 3 inches).

Anyone on a long trip can move. The Yellow Book says it makes sense to advise frequent walks and calf exercises, while noting that the proof is mostly indirect⁴. Point your toes up and down at the ankle every so often, and walk the aisle or stop the car every couple of hours.

People at higher risk need more. For them, the Yellow Book cites chest physicians’ guidance for trips over six hours: choose an aisle seat and wear well-fitted, below-the-knee compression stockings rated 15 to 30 mm Hg at the ankle⁴.

A 2021 Cochrane review of 12 trials with 2,918 people backs the stockings. On flights of more than five hours, stockings cut clots that cause no symptoms from a few dozen per 1,000 passengers to two or three, with high-certainty evidence⁵. No trial passenger had a clot with symptoms, so the effect on those is unknown⁵.

Keep drinking water for comfort, but don’t count on it to stop a clot: CDC finds no evidence tying travel clots to dehydration⁴. Leg swelling or pain in the weeks after a trip deserves a call to your doctor. Sudden shortness of breath or chest pain needs emergency care.

Cabin air is dry, but it’s well filtered

Airplane cabin air usually runs about 10% to 20% humidity, which can dry out your nose, throat and eyes⁶. Saline spray, eye drops and a water bottle are cheap comforts.

Cabins are pressurized to the equivalent of about 6,000 to 8,000 feet⁶. Most healthy travelers notice nothing. People with anemia or heart, lung or blood-vessel disease of the brain can get worse, so they should talk to a clinician before flying⁶.

The air itself is better than many people think. On large jets, recirculated air passes through HEPA filters that catch 99.97% of particles 0.3 microns or larger, and cabin air is replaced 20 to 30 times an hour⁶. The weak spots are boarding, deplaning and delays, when ventilation may be off⁶. Clean hands and a well-fitting mask during those times are options⁶.

Jet lag: let light do the heavy lifting

Jet lag sets in when you cross at least two time zones. Flying east is harder, and the body clock shifts only about an hour a day going east and 1.5 hours a day going west⁷.

Light is the free tool. After flying east, get bright morning light and dim your evenings. After flying west, avoid bright early-morning light and stay up until local bedtime⁷. For trips shorter than two days, CDC suggests staying on home time⁷.

Melatonin is the rare travel supplement with expert backing. Among the standard options the American Academy of Sleep Medicine names for frequent travelers with jet lag is melatonin taken at set times⁷. CDC notes that a small dose, 0.5 to 1 mg, often shifts the body clock, and it advises against more than 5 mg⁷.

Because it’s sold as a supplement, the amount in the bottle may not match the label⁷. Later articles in this series cover sleep on the road and melatonin in depth.

Motion sickness: what helps and what’s mostly hope

Your body learns. CDC calls habituation, or gradual repeated exposure, the most effective defense, though it takes time⁸.

Seating helps, too. Sit over the wings on a plane and away from the front of a boat, look at the horizon and skip reading⁸. Slow, controlled breathing worked about half as well as motion sickness drugs in lab trials, with no side effects⁸.

The natural favorites get a mixed report. CDC calls the evidence for ginger weak and contradictory⁸. Acupressure wristbands did no better than placebo in lab trials, though placebo effects can be strong⁸. Ginger tea is a low-cost thing to try if it agrees with you, but don’t count on it for a rough ferry.

Drugs work best taken before symptoms start. Meclizine and dimenhydrinate suit mild to moderate motion, while non-drowsy allergy pills such as loratadine don’t help because they don’t reach the brain⁸. A scopolamine patch lasts about three days but needs six to eight hours to work, and it isn’t for people with glaucoma or children⁸. Drowsiness is the common side effect.

Medicines and supplements at the border

Some of the strictest rules travelers meet are about pills. The State Department warns that a medicine legal in the U.S. may be illegal elsewhere and could lead to arrest¹⁰. It singles out ADHD medicines, sleeping pills and medical marijuana as items to check¹⁰.

Japan is a clear example. The State Department says Adderall, commonly prescribed in the U.S., is illegal there, U.S. prescriptions aren’t honored, and CBD products may be illegal depending on their THC content¹¹.

Supplements can cross categories, too. Melatonin sits on open shelves in American stores, but in the UK it is a prescription-only medicine, according to the National Health Service¹². Don’t plan on buying it there.

Your homework starts with embassies. Contact the embassy of each country on your route, including layover stops, about permits or limits¹⁰. Pack pills in the pharmacy packaging they came in, with a letter from your doctor that lists each one by its generic name¹⁰. Carry the full trip’s supply plus a few extra days’ worth in case of delays¹⁰.

Coming home has rules, too. U.S. Customs and Border Protection asks travelers to declare all medicines, keep prescriptions in their original labeled containers and carry no more than a personal-use supply, about 90 days as a rule of thumb¹³. If pills aren’t in the original bottle, bring a copy of the prescription or a doctor’s letter¹³.

Plan for care, too. Medicare doesn’t cover care outside the U.S., and an air ambulance flight home can cost roughly $20,000 to $200,000¹⁰. Check your insurance before you leave.

Vaccines and the pre-trip visit, on your terms

Many natural-health readers weigh vaccines carefully, and that’s their right. The fair way to decide is with the real risks of your destination in view.

Measles spreads easily, and it often reaches the U.S. through travelers. CDC says about 2 of every 3 unvaccinated travelers who bring measles back are Americans¹⁴. Two doses of MMR vaccine are about 97% effective, and one dose is about 93%¹⁴. Adults and children 12 months and older without proof of immunity should get vaccinated at least two weeks before leaving, and infants 6 to 11 months can get an early dose¹⁴.

Hepatitis A, a liver infection, is among the most common vaccine-preventable infections caught during travel¹⁵. It spreads through contaminated food and water, survives freezing, and can infect travelers on ordinary tourist routes¹⁵. It rarely causes liver failure, but that risk is higher in older adults and people with liver disease¹⁵. More than 90% of people have protective antibodies a month after the first vaccine dose¹⁵.

A pre-trip visit is also the place to review the herbs and supplements you take alongside any travel medicines. Bring the bottles.

Your travel wellness kit and first-72-hours plan

Your body’s own rhythms of light, sleep, movement and food are the best travel tools you have. The kit covers the few things they can’t.

The first 72 hours

1. On the way. Move your ankles often, walk when you can and keep water handy. Skip heavy drinking, which breaks up sleep⁷.
2. Day 1. Get outside in daylight at the right time for your direction of travel⁷. Take a walk to learn the neighborhood. Eat a light, familiar meal and wash your hands before eating.
3. Day 1 and 2. Keep naps short, about 20 to 30 minutes, and use caffeine only in the local daytime⁷.
4. Day 2 and 3. Plan sun breaks. Protect your skin when the UV index is 3 or higher, and reapply sunscreen after two hours or after swimming or sweating⁹. Remember that water, sand and snow reflect UV rays⁹.
5. Day 3. Check in with yourself. Watch for diarrhea that won’t quit, leg swelling or a bad sunburn, and get care early.

What the evidence shows

Approach	Evidence rating	What it rests on
Compression stockings on long flights	Strong evidence for fewer symptomless clots; effect on clots with symptoms unknown	Cochrane review of 12 trials5
Walking and calf exercises	Promising but early	Mostly indirect evidence4
Bismuth subsalicylate to prevent diarrhea	Promising but early	About half as many cases, but in studies from one country, Mexico1
Probiotics to prevent diarrhea	Not enough evidence	Small studies, varied products1
Timed melatonin for jet lag	Strong evidence	Listed as a standard treatment by the American Academy of Sleep Medicine, per CDC7
Ginger for motion sickness	Not enough evidence	Weak and contradictory results8
Acupressure wristbands	Evidence says no, or unsafe	No better than placebo in lab trials8
MMR vaccine for measles	Strong evidence	About 97% effective after two doses14

Questions readers ask

The bottom line

The biggest travel threats are ordinary ones, and so are the best defenses. Wash your hands, keep moving on long rides, use daylight to reset your clock, respect the sun and plan for fluids if your stomach turns.

Skip the cabinet of travel supplements. Check the medicine rules for every border you’ll cross, carry what you need in labeled bottles, and make vaccine decisions with your destination’s real risks in view.

Related reading

• The healthiest natural habits cost little, and these are the places money still matters
• Your immune system works more like a team than a volume knob, and some habits help it
• What happens when you don’t tell your doctor about supplements
• Every health choice trades benefit for risk, including doing nothing
• The symptoms that mean call 911 now

Sources

1. Connor BA, Leung DT. “Travelers’ Diarrhea.” CDC Yellow Book: Health Information for International Travel, 2026 edition. CDC, 2025. cdc.gov
2. Federal Trade Commission. “Makers of Airborne Settle FTC Charges of Deceptive Advertising; Agreement Brings Total Settlement Funds to $30 Million.” FTC, August 14, 2008. ftc.gov
3. World Health Organization. “Study Results Released on Travel and Blood Clots.” WHO, June 29, 2007. who.int
4. Reyes NL, Abe K. “Deep Vein Thrombosis and Pulmonary Embolism.” CDC Yellow Book, 2026 edition. CDC, April 23, 2025. cdc.gov
5. Clarke MJ, Broderick C, Hopewell S, Juszczak E, Eisinga A. “Compression Stockings for Preventing Deep Vein Thrombosis in Airline Passengers.” Cochrane Database of Systematic Reviews, 2021, CD004002. cochranelibrary.com
6. Mase SR, Gearhart SL, Nardell EA, Brown CM. “Air Travel.” CDC Yellow Book, 2026 edition. CDC, April 23, 2025. cdc.gov
7. Riedy SM, Williams SG. “Jet Lag Disorder.” CDC Yellow Book, 2026 edition. CDC, 2025. cdc.gov
8. Golding JF. “Motion Sickness.” CDC Yellow Book, 2026 edition. CDC, 2025. cdc.gov
9. Centers for Disease Control and Prevention. “Sun Safety.” CDC, June 17, 2026. cdc.gov
10. U.S. Department of State. “Medicine and Health.” Bureau of Consular Affairs, updated August 11, 2025. travel.state.gov
11. U.S. Department of State. “Japan Travel Advisory” (travel guidance). Bureau of Consular Affairs, 2026. travel.state.gov
12. National Health Service (England). “About Melatonin.” NHS, reviewed February 13, 2023. nhs.uk
13. U.S. Customs and Border Protection. “Travel Tips Ensure Smooth CBP Processing Experience.” CBP, May 23, 2019. cbp.gov
14. Centers for Disease Control and Prevention. “Plan for Travel” (measles). CDC, April 29, 2026. cdc.gov
15. CDC Yellow Book, 2026 edition. “Hepatitis A.” CDC, April 23, 2025. cdc.gov