Accelerated stability studies of Emblica officinalis, Terminalia belerica and Terminalia chebula have been carried out as per ICH guidelines and its effect on total polyphenol content as determined by Folin-Ciocalteu method and Gallic acid content as determined by HPLC (High Performance Liquid Chromatography) was studied. The samples were kept in stability chamber at 40°C and 75% relative humidity for 3 months for accelerated stability studies. Samples were taken out at periodic intervals and extracted to determine total polyphenol content by spectrophotometric method and gallic acid content by HPLC. The HPLC method was also validated to demonstrate its selectivity, linearity, precision, and accuracy. The results indicate an increase in total polyphenolic content as well gallic acid content under accelerated stability conditions which is indicative of hydrolysis of gallotannic acids present in crude drugs to liberate free gallic acid, thereby increasing the total polyphenolic content.