Medicinal products in Japan are regulated by the Pharmaceutical Affairs Law (PAL) and represent four distinguished types. The Article 1 of PAL stipulates that "This law is intended to provide regulations required to ensure the quality, efficacy and safety of drugs, quasi-drugs, cosmetics and medical devices and to improve the public health and hygiene through necessary measures taken to promote the research and development of drugs and medical devices, which are of particular importance to the medical practice."

The four specific types of products are sometime collectively referred in English as "medicinal products", or less frequently abbreviated to "drugs, etc."  In JAD edition, whenever appropriate the term medicinal products is used.

The four types of the regulated medicinal products in Japan are defined as follow:

• drugs - In some texts translated from Japanese to English, the actual Japanese term “iyakuhin” is translated as “medicines”, and in other texts – as “drugs”. From regulatory point, the Japanese term iyakuhin covers both pharmaceuticals and biologics, prescription and non-prescription products, reimbursed and not reimbursed products, branded and generic products. 

• quasi-drugs - not presently included in JAD

• cosmetics - not presently included in JAD

• medical devices - data to be included in the separate JAD Medical Devices database

The products which profiles are included in JAD database are predominantly newly approved drugs, branded pharmaceuticals and biological products, including some Active Pharmaceutical Ingredients (API).