Gandhak Rasayan ((also spelled as Gandhaka Rasayana)) is a Sulphur based Ayurvedic preparation. It is prepared by processing purified Sulphur in herbal ingredients. Sulphur/Sulfur is known as ‘Gandhak’ in Sanskrit and Hindi due to its strong peculiar rotten-egg like smell. It is a non-metallic element found in nature. There are four varieties of Sulphur viz. red, yellow, white and black. Of these the red and black are not available now. Yellow variety is used for internal use and white is used for topical application.