Asian Journal of Medicine and Health

Ritucharya, the seasonal regimen codified in the classical Ayurvedic compendia, prescribes graded adjustments to diet and conduct in accordance with the annual cycle, with the explicit aim of preventing disease and preserving health. As non-communicable and seasonally patterned illnesses continue to dominate the global burden of mortality, season-sensitive preventive frameworks have acquired renewed relevance, and Ritucharya is increasingly invoked as an ancient precedent for such approaches. This review critically evaluates the strength, coherence and limitations of the evidence bearing on Ritucharya, distinguishing its internal classical logic from claims about its physiological validity and clinical effectiveness. The classical scheme is first reconstructed as a coherent theoretical system built on the solar half-years, doshic accumulation and pacification, the seasonal behaviour of digestive capacity, and the transitional vulnerability of inter-seasonal periods. Contemporary evidence is then examined across three domains that the regimen implicitly engages: the chronobiological organisation of human physiology, including documented annual variation in immune and metabolic gene expression; the seasonal restructuring of the gut microbiome and its links to diet, cold and energy balance; and the seasonality of cardiovascular and infectious disease. Across these domains, the biological plausibility of a season-adaptive regimen is reasonably well supported by mechanistic and epidemiological work of moderate to high quality, and several specific classical recommendations show qualitative congruence with modern findings. The direct clinical evidence for Ritucharya as an intervention is, by contrast, sparse, methodologically weak and concentrated in lower-tier outlets, and constitution-based individualisation rests on preliminary and partly inconsistent data. The regimen is therefore best characterised as a biologically plausible and historically sophisticated preventive heuristic whose specific efficacy claims remain largely untested. Priorities for rigorous prospective evaluation, standardised operationalisation and mechanistically anchored outcome measurement are proposed. The synthesis is intended to support disciplined integration rather than either uncritical endorsement or premature dismissal.