How do you stay healthy when traveling internationally? And what do you pack in case you get sick? Every location has its own set of challenges, recommended vaccines and access to pharmacies.

There’s a thin line between being over- and underprepared, said Rebecca Acosta, the co-founder and executive director of Traveler’s Medical Service. The average globe-trotting traveler does not need IV bags and syringes, she said, though the items are suggested for those trekking in rural areas.

Here are some tips on how to pack a first-aid kit, whether you are going around the world for a year or a remote adventure for a week.

Start with a vaccine checklist

The Centers for Disease Control has a list of vaccines, health notices and packing lists for those traveling around the world.

Make sure to look up vaccine requirements far in advance of your travels, as some vaccines may require treatments or doses. Additionally, some nations may require proof of vaccination upon entering customs. The World Health Organization keeps an updated list of nations requiring yellow fever vaccines.

Don’t forget travel insurance

If you are traveling with a group or on business, you may already have traveler’s insurance that covers medical evacuation. If not, consider buying insurance that includes medevac services, which are recommended when traveling to more rural destinations.

In addition to health coverage, travel insurance covers things like lost baggage and flight cancellations. So even if you stay healthy, it can come in handy when you’re on road.

A good travel insurance package will also include a support number to call if you need help identifying the severity of your illness, and where to turn for help.

If your health care provider in the United States offers virtual doctor visits, you may be able to turn to your regular doctor’s office while abroad, too.

Management vs. prevention

If you have prescriptions, make sure they are filled for the entirety of your travels. That may take some coordinating between a primary care physician and insurance companies if medicines need to be resupplied on the road. Acosta recommends working with a doctor to compile a list of all prescribed medications, in generic form, in case prescriptions are misplaced.

When it comes to prevention, Acosta said, travelers should think of their medicine cabinet. “What are the types of things that you may grab from your medical kit at home? If it’s one in the morning and you have an upset stomach or a headache, what do you go for?”

Pack those items first.

Build your kit

Travelers should create a first-aid kit for simple wounds and basic medications to treat stomach issues, colds and allergies.

“The worst time to go looking for a pharmacy is after you already need one — and that’s especially true when you’re traveling in an unfamiliar place,” said Ria Misra, the travel editor with Wirecutter, a New York Times Co. entity that reviews and recommends products. That’s why she recommends building your own kit or carefully choosing a prepackaged one.

Choose the brands that you’ve used in the past. (Traveling internationally is not a great time to test new medication.) Wirecutter recommends packaging a kit in the Osprey UltraLight Roll Organizer; the bag’s roll-up design allows it to pack down significantly.

For travelers short on time, some prepacked first-aid kits cover the basics. Wirecutter recommends First Aid Only’s Essentials Kit, which contains the basics needed to clean up minor cuts and relieve pain.

Keep those kits in a carry-on.