Whilst Professor of Surgery at the Calcutta Medical College, Dr Fayrer studied all aspects of snake poisoning. His work, The Thanatophidia of India being a Description of the Venomous Snakes of the Indian Peninsula, with an Account of the Influence of their Poison of Life; and a Series of Experiments was published in 1872. Collating information from official Government records of death due to snakebite, Fayrer recorded a mortality of 11,416 persons for the year 1869 in the Presidency of Bengal and estimated a mortality of more than 20,000 for all British India. In 1872, working in London with Lauder Brunton, Fayrer studied the physiological action on Naja naja venom in more detail. Respiratory paralysis was due to a curare-like blockade of the neuromuscular junction, and they believed, a central effect also; artificial respiration was ineffective in producing recovery. A large dose of cobra venom was observed to induce tetanic contraction of the heart both in vivo and in vitro. As President of the Medical Board of the India Office in London from 1873 to 1895, Sir Joseph Fayrer was much concerned with cholera epidemics which resulted in an average mortality of over 200,000 persons annually. In 1885, he represented the Indian Government at the fourth International Conference on Cholera, a fore-runner of the World Health Organization.