Medicine are taken to cure illness. Medicine can cure many illnesses such as fevers, stomach pains, catarrh, cold, headach e.t.c.
Some medicine or drugs can be bought off the SHELF, why some can only be bought by DOCTOR'S PRESCRIPTION. If you are sick, then you should get a prescription from a qualified doctor. You should not buy medicine from people in the markets or on road side.
Drugs is another word for medicine. Taking an overdose of dugs or the wrong use of drugs or using drugs without doctor's prescription is called DRUG ABUSE.