From Edinburgh he went to Leyden, where he studied anatomy under the famous anatomist Bernhard Siegfried Albinus.

According to the Dictionary of National Biography, his habits had always been such as to try his constitution; and in early life, it is said, he often reconciled the claims of pleasure and business by lecturing for three hours in the morning without having gone to bed the night before.

In 1783, with John Hunter, he assisted in setting up a small society of physicians and surgeons, which later published several volumes of transactions under the title of Transactions of a Society for the improvement of medical and chirurgical knowledge, and attended its meetings regularly until shortly before his death.

[3] As reported in The Epicure's Almanack (1815, page 3), Fordyce dined daily at Dolly's Chophouse: In 1762 he married the daughter of Charles Stuart, Esq., conservator of Scottish privileges in the United Netherlands, by whom he had four children: two sons and two daughters.

He died in London in 1802, of disorders connected with gout, and was buried at St Anne's, Soho.