“What medication would you recommend to prevent travel sickness?”

I think by "travel sickness" you might mean traveler's diarrhea. You don't need to take anything BEFORE you get diarrhea, but it is appropriate to treat it AFTER diarrhea develops. To treat this, you can take antibiotics with you on the trip in case you develop diarrhea. Common antibiotics for this purpose are cipro, flagyl or xifaxan. But you need to find a doctor to prescribe these before you travel.

I have always used over the counter dramamine. There are prescriptions such as meclizine and scopolamine, however you should not operate a vehicle if taking medication. A natural alternative is ginger

Dramamine. Or Halcyon if you are not driving (it may make you sleepy).

I have had car sickness my whole life and I know it is miserable. The best solution for me is to be the driver. I generally don't get car sickness when I drive. You can try dramamine over the counter but it typically causes some drowsiness. My ultimate treatment for travel sickness is a scopolamine patch. Brandname is Transderm. It is a prescription however. One thing I would say if you try the patch is to be careful not to get the sticky stuff on your fingers and then inadvertently rub your eye. If that happens you will have one pupil that won't contract for 3 days. Even though you know that this is from the medication you convince yourself that you have a brain tumor and this is your last vacation. Speaking from experience. If I accidentally touch the patch, I make sure to wash my hands.

Over-the-counter Bonine helps, and antivert, which is by prescription. Ginger is very helpful and you can buy it dried or in losenges. If your road sickness is really bad, scopalamine patch may be helpful. But most oral meds work well.