Browse the above categories to see what you think you’ll need a first aid kit for, then consider your own medical training. First aid kits aren’t light, so don’t bring anything you can’t imagine yourself needing or don’t feel comfortable using. I would say the bare minimum should be some antiseptic wipes, ibuprofen/acetaminophen, antibacterial ointment, athletic tape, and bandaids—and then build your kit from there based on where you’re going and what you’re doing.