'''Parah ''' is the name of a treatise in the Mishnah and the Tosefta, included in the order Tohorot. The Pentateuchal law ( Num. ) decrees that a red heifer, "wherein is no blemish, and upon which never came yoke," shall be burned and her ashes mixed with spring water, that the compound so obtained may be used to sprinkle and cleanse every one who becomes unclean. The burning of the heifer and the preparation of the ashes, as well as the fetching of the water and its mixture for sprinkling, were attended by strict ceremonies. The treatise Parah contains a detailed description of these ceremonies, as well as various regulations concerning the purity of the water for sprinkling and its different effects.
In most editions the treatise is the fourth in the mishnaic order Tohorot, and is divided into twelve chapters, containing ninety-six paragraphs in all.