Amrtottarakvatha is a decoction which is used primarily in the management of hyperpyrexia (jwara). Specific plant parts of Tinosporacordifolia (Willd.) Miers.,Terminaliachebula Retz., and ZingiberoffficinaleRoscoe. are its ingredients. Only nine compounds have been reported from this polyherbal formulation. In the current study a simple and precise high performance thin layer chromatographic (HPTLC) method was developed for identification and quantification of an unreported compound Ellagic acid in this decoction. Ellagic acid is one of the major compounds in Terminalia chebula Retz. The HPTLC method used aluminium plates pre-coated with silica gel 60F254 as the stationary phase and Toluene:Methanol:Ethyl acetate: Formic acid (4:1:4:1, v/v) as solvent system. This system gave compact spot for Ellagic acid (Rf: 0.39 ? 0.0038).The method was validated for specificity, linearity and precision. The limit of detection and quantification were 0.52 ng and 1.577 ng respectively. The amount of Ellagic acid in Amrtottara kvatha was estimated as 0.050?0.016 % w/w by the developed method. The method for identification and quantification of Ellagic acid in Amrtottara kvatha can be used in pharmacological exploration and standardization of Amrtottarakvatha.