There’s nothing that can derail a good vacation like feeling ill. When I was a kid on a family trip to Mexico, my mom fell so ill that a doctor had to come administer a shot in our hotel room. I remember checking out museums, churches, and neighborhoods with my father and brother, my poor mom stuck in bed back at the hotel. Two years ago, one of our sons caught a stomach bug during a cruise, which is the last place you want to be when that happens. Thankfully, it was toward the end of our trip, and no one else got sick. Even vacations aren’t immune to illness. Whether it’s the flu, jet lag, or a new food that simply didn’t agree with you, it’s good to have things on hand that will help you stay healthy on vacation. Here are nine ideas for your next trip.