Enteric methane production from dairy cattle represents a significant source of greenhouse-gas emissions and also reflects a loss of dietary energy from the rumen. The present study aims to evaluate a novel polyherbal formulation comprising Madhuca longifolia, Moringa oleifera, Ocimum tenuiflorum, Cinnamomum tamala and Punica granatum for its potential to reduce ruminal methane production under in-vitro conditions. The selected plants were chosen based on their complementary phytochemical constituents, including tannins, phenolics, flavonoids, saponins and essential-oil components, which may influence rumen microbial fermentation and methanogenesis. Each herbal material will initially be screened individually at graded inclusion levels using an anaerobic in-vitro rumen fermentation system. The treatments will be evaluated for total gas production, methane production, methane percentage, pH, in-vitro dry matter digestibility, ammonia-nitrogen and volatile fatty acid production. Based on the individual screening results, the most effective herbal materials will be combined at different proportions to develop and optimize a polyherbal formulation with maximum methane-mitigation efficiency and minimal adverse effects on rumen fermentation. The optimized formulation will subsequently be compared with the untreated control to determine its overall antimethanogenic potential. The study is expected to establish a relationship between herbal phytochemical characteristics and rumen fermentation responses and identify an effective plant-based strategy for reducing enteric methane production while maintaining nutrient digestibility and desirable fermentation characteristics. The findings may provide a scientific basis for developing sustainable phytogenic feed additives for methane mitigation in dairy cattle.