Answer:
In pharmacy drug are also called medicine and are used for bringing or sustaining well-being of a person either by curing, preventions like prophylaxis, diagnosis like barium meal, elevating pains like analgesics and placebo too. A drug may or may not be helpful like in the case of illicit drugs. Pharmaceutically all medicines are drugs. But clinically not all drugs are medicines. Drugs, most of which would be medications that are illegal to produce, own use or sell. Drug is the main chemical component in a medicine. That is why a placebo can not be a drug. When a drug is mixed with other pharmaceutical ingredients, medicine is obtained as a final product.