1. A. Both kinds of drugs are dangerous if you don't follow the directions. B isn't necessarily true, cause while prescription drugs are regulated, some kinds of over the counter drugs you can buy and take as much as you can get your hands on. C is ridiculous. D doesn't make much sense either.
2. D. Hives are a harmful side effect. Chills are uncomfortable, but I don't think they cause any lasting damage to your body. The other two aren't bad, they're what you took the medicine for!
3. C. I don't think A is correct because pain can't necessarily be described as good health (plus I don't think they give you painkillers for that). B is a vitamin deficiency, which is an illness. D is an infection, also an illness.