Humans have had a history of association with mercury since the earliest records. This relationship has had many quixotic elements, but has on many occasions and in many ways impinged upon the kidneys. Arabic physicians used mercury to treat skin infections, urinary infections and urethral stones. The rise of syphilis in Europe in the 16th century saw its application as the primary treatment, sometimes oral and sometimes parenteral, of patients suffering from that disease until the mid-20th century. It also found various other uses. Mercurial diuretics originated from chance observations of such patients, and these received much use in the first half of the 20th century until safer and more efficacious nonmercurial diuretics replaced them. Many physicians viewed mercury as a panacea, but others challenged their views. Its use was always recognised to have potential complications, but realisation of its ability to cause acute kidney injury, chronic renal impairment and nephrotic syndrome gradually evolved, and it was phased out of therapeutics. A further contribution it made to nephrology lay in the manufacture of thermometers, sphygmomanometers and cystoscopes.