We have shown the necessity of substantiation of the status of pharmacy as an independent science and theoretical comprehension of pharmacy as a system of scientific knowledge. Pharmacy should find the principles of theoretic unity of its knowledge in the specifics of pharmaceutical activity. We have carried out gnoseological analysis of the sphere of interests of chemistry, medicine, toxicology and pharmacy in the field of studying the drugs. Pharmaceutical aspects of a drug as an object of pharmaceutical activity have been shown. We have studied the regularities between the structure of a drug and the range of its biological activity in order to work out the methods of its analysis and synthesis. A drug is viewed as an object of analysis and synthesis in order to define its quality and ‘behavior’ in a human body. We have characterized the technological aspect of studying a drug. It has been noted that technical and pharmaceutical view on drugs manufacture is determined by biopharmaceutical factors. Only pharmacy views a drug as a product. We have defined product, ethic and ecological characteristics of a drug. We have worked out the scheme of pharmacy’s subject and activity system formation. The main component of the system is a drug. The peculiarities of the subject of pharmaceutical activity and the tasks performed by a pharmacist define the specifics of a pharmacist’s professional thinking and peculiarities of knowledge management in the system under study.