After 1856 Keith devoted himself to surgery and in particular to the then new and controversial procedure of
ovariotomy. The first documented successful performance of this procedure was by
Ephraim McDowell (1771–1830) in Kentucky in 1809. McDowell had studied surgery in Edinburgh under
John Bell (1763–1820) who described the operation but never performed it. Bell's successor in Edinburgh
John Lizars (1787–1860), was sent McDowell's account and he performed the first successful ovariotomy in Britain, publishing the results in 1825. Surgeons like
Charles Clay (1801–1893) in Manchester and
Thomas Spencer Wells (1818–1897) in London began to perform the procedure regularly, but the mortality rate was so high that mainstream medical opinion felt that it was too dangerous to perform. Keith performed his first ovariotomy in 1862, having learned the technique from
Spencer Wells. than that of other published series like Spencer Wells. Keith further reduced the mortality rate to 4% when he began to use antiseptic technique, taught to him by his lifelong friend
Joseph Lister. The leading American gynaecologist
J. Marion Sims (1813–1883) visited Keith to find the ‘secret’ of these remarkable results and concluded that Keith's meticulous attention to detail was largely responsible for his ‘success which so outstripped that of all other operators, that it became a wonder and admiration of surgeons all over the world.’ Keith gained a worldwide reputation. He began to perform the hysterectomy procedure, again with low mortality compared to other published series. In 1888 Keith moved to London, living at Charles Street, Berkeley Square. His reputation was such that he was consulted by eminent people such as
Lady Randolph Churchill (1854–1921), but his years here were dogged by ill health. The congenital
cystinuria, which had caused him to pass
urinary calculi from childhood and had required operations, now caused a renal abscess which drained by his son and surgical partner Skene Keith (1858–1919. He attributed some of his health problems to the large quantities of bicarbonate which he took to combat the condition and his repeated exposure to antiseptic agents may also have been a factor in his death at the age of 67. He died early on the morning of Wednesday, 9 October 1895 and was buried in
Kensal Green Cemetery. A memorial to Keith also lies in his home at St Cyrus churchyard. ==Family==