It is recorded that Sir Hans Sloane was introduced to cocoa as a drink in Jamaica during his stay in the 1680's. He apparently found it 'nauseous' but mixing it with milk made it more palatable.

He took this chocolate recipe to England on his return where it was manufactured and at first sold by apothecaries as a medicine. Much later, Cadburys manufactured chocolate using Sloane's recipe.

Source: Prof. Robert J. Lancashire, University of the West Indies.