Mary Broadfoot Walker (17 April 1888 – 13 September 1974) was a Scottish physician who first demonstrated the effectiveness of physostigmine in the treatment of the condition myasthenia gravis, a disease relating to muscle weakness.

[2] In 1920 she became a salaried Assistant Medical Officer in "Poor Law Service" at St Alfege's Hospital, Greenwich, London, where she worked until 1936.

[citation needed] In 1934, while working at St Alfege's Hospital, Walker discovered that the subcutaneous injection of physostigmine could temporarily reverse the muscle weakness found in patients with myasthenia gravis.

[9] After her retirement to Croft-an-Righ in 1954,[1] she continued to work part-time at the Glasgow Royal Maternity and Women's Hospital, and remained active in the field of myasthenia gravis.

[1] In 1962, Walker was the first recipient of the Royal College of Physicians Jean Hunter Prize "for the advancement of research into the treatment of nervous exhaustion and for her original contribution to the fundamental knowledge of the nature of myasthenia gravis, made while carrying out the routine duties of a medical officer at a large metropolitan hospital".