Ratanjot is attributed to eight species of Boraginacae species belonging to genera Alkanna, Arnebia, Maharanga and Onosma and regarded as one of the important herbal drugs of indigenous systems of medicine. The root and root stock, which form the actual drug, are considered to be an anthelmintic, antipyretic and antiseptic. They are also claimed to be useful in burn, eczema, wounds and eruptions, and used for treating the diseases of eyes, bronchitis, abdominal pains, itch, etc. Several workers reported that the Naphthaquinones (arnebins), the main active constituents of the drug, are responsible for its colour and therapeutic efficacy. It is claimed that the Arnebia nobilis was imported to India from Afghanistan but the red coloured roots resembling with A. nobilis were found to be gathered by local people for commercial purposes during the course of botanical surey of Himalayan region. Hence, it is decided to evaluate Arnebia nobilis pharmacognostically. The important macro-microscopic features of this species are roots 1-5 cm broad; outermost xylem with broad vessels and innermost with groups of radially arranged narrow vessels while the middle region occupied by alternate rings of clusters of broad and narrow vessels and presence of pith. Besides the percentage of arnebin-1, -3 and 4 are 9.37, 10.53 and 1.72 respectively.