AUSHADHA SEVANA KALA: A COMPREHENSIVE REVIEW OF CLASSICAL CONCEPT AND MODERN CORRELATION

Ayurveda, one of the oldest systems of medicine, presents a comprehensive approach to health and disease through the classical concept of Trisutra—Hetu (etiological factors), Linga (signs and symptoms), and Aushadha (therapeutics) Among these, Aushadha is not merely concerned with the selection of an appropriate medicine; its therapeutic potential is also closely linked with when, how, and under which physiological conditions it is administered. The classical concept of Aushadha Sevana Kala reflects this time-dependent approach to therapeutics, wherein the timing of medication is determined by factors such as Dosha predominance, Avastha of Agni, Rogi Bala, Roga Bala, Ahara, and the stage of disease. Acharya Vagbhata aptly emphasized the principle of “Kalo Bhaisajya Yoga,” highlighting the importance of selecting an appropriate time for drug administration to achieve the intended therapeutic outcome. Similarly, Acharya Charaka described that medicine administered at the appropriate time produces superior therapeutic effects compared with administration at an inappropriate time. Thus, Ayurveda appears to recognize that the efficacy of a medicine is influenced not only by what is administered, but also by when it is administered. This review explores the classical concept, classification, determinants, and therapeutic rationale of Aushadha Sevana Kala, with particular emphasis on its relationship with Ahara, Agni, Dosha, and disease condition. Furthermore, an attempt is made to examine its conceptual correlation with contemporary principles of drug absorption, bioavailability, pharmacokinetics, pharmacodynamics, and chronotherapy. Understanding this time-oriented therapeutic principle may provide a meaningful perspective toward individualized and rational drug administration in contemporary Ayurvedic practice. The review therefore aims to bridge the classical wisdom of Aushadha Sevana Kala with emerging concepts of time-dependent therapeutics and explore its potential relevance in modern clinical practice.