Always grab a ziploc bag and put daytime/nighttime cold medicine...diahrrea medicine, over the counter pain meds, seasick pills, bag with bandages, spray antiseptic and neospirin, eyedrops,over the counter sleep aides.
If you wish to purchase on the ship or on shore.......$$$$$$$ even for a simple bandaid.
Somehow, someway you will need one of these items and you will be happy to have them.