Diagnosis and treatment of diseases relies on the understanding of abnormality in temperaments and the equable human and drug temperaments. Temperament is a quality produced by interaction of opposite qualities present in very tiny elements. In rational classification, temperaments are divided into true equable and inequable ones. In the true equable temperament, the amounts of opposite qualities are the same. However, such temperament does not exist. Contrary to the true equable temperament, the inequable temperament is inclined towards one or two qualities of hotness, coldness, dryness, or wetness. In medicine, human equatability is compared with the inequable temperaments from eight aspects and with respect to genus, species, individual, and organ. Human inequable temperaments are also categorized into eight types, all of which are opposite to the equable temperaments.
Other types of human temperaments include with and without matter temperaments, temperaments of organs, temperaments of different ages, obesity and thinness temperaments, temperament according to sex, and habit temperament. Temperaments of drugs are also grouped into two main categories of equable and inequable. Other drug temperaments are combined temperament, primary temperament, secondary temperament, robust or stable secondary temperament, and weak or unstable secondary temperament. In this paper, we have described the human and drug temperaments to provide a novel scientific approach to the disease and treatment entities. We hope that carrying out research in this field result in providing appropriate therapeutic approaches with respect to the patient and drug temperaments and subsequently achieving more desirable effects of various drugs in different people.