Valentine Greatrakes, an Irish quack, born at Affane, county Waterford, Feb. 14, 1628, died in Dublin, probably about 1700. He was educated at Trinity college, Dublin, and on the outbreak of the rebellion went to England, where he devoted some time to the study of the classics and divinity. He served in the parliamentary army from 1649 to 1656, when he returned to Ireland and was made a justice of the peace in county Cork, and held other offices which were taken from him at the restoration. Soon afterward he claimed the power to cure the king's evil and all other diseases by the touch; and in 1665 he went to London, where the king invited him to Whitehall, and where he is alleged to have performed many cures, which were attested by Robert Boyle, Sir John Godolphin, and many other eminent persons. Dr. Henry Stubbe published a pamphlet in praise of Greatrakes's skill, under the title "The Miraculist Conformist" (Oxford, 1666). Greatrakes having failed in one instance to effect a cure, David Lloyd published a pamphlet entitled "Wonders no Miracles" (London, 1666), in which he denounced him as a cheat.

To this Greatrakes replied in a letter addressed to Boyle, entitled "Account of Val. Greatrakes and divers of his strange Cures." In 1667 he returned to Ireland.