Medicine, medication and drug

Please help me distinguish between medicine, medication and drug.

medicine: the science of disease treatment and health maintenance, it can also refer to a specific drug

medication: drug

drug: natural or artificial substance used to cure diseases[YSaerTTEW443543]

TOEIC listening, question-response: Should I leave a voice mail if Ms. Dawkins is not there?[YSaerTTEW443543]