For malaria--we had our then-7 yr old and 14 yr old take oral meds shortly before our ABD trip to China, without any problem. In China, ABD was very good about giving us bottled water, and they scout out areas for clean bathrooms, risk-free (and sanitary) restaurants and the like. One parent had a bout of stomach flu, but we don't know where that came from--probably more related to the long flight, or possibly airline food (there were a couple of internal flights where Disney had us take our own lunches rather than eat the airline's food). As I understand it, there are different ways to take the malaria drug--seemed like the most common was 4 doses spread over a number of days just before you travel (pills); difficult if your child has trouble swalling moderately sized pills. There may be a liquid--not sure about that.