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John Harvey Kellogg, M.D. (February 26, 1852 - December 14, 1943) was an American medical doctor, nutritionist, inventor, health activist, and businessman. He was the director of the Battle Creek Sanitarium in Battle Creek, Michigan. The sanitarium was founded by members of the Seventh-day Adventist Church. It combined aspects of a European spa, a hydrotherapy institution, a hospital and a high-class hotel.

Although they are less discussed than his food creations, Kellogg designed and improved upon a number of medical devices that were regularly used at the Battle Creek Sanitarium in surgical operations and in treatment modalities falling under the term "physiotherapy". Many of the machines invented by Kellogg were manufactured by the Battle Creek Sanitarium Equipment Company, which was established in 1890. Dr. Kellogg attempted to popularize these treatment methods, including electrotherapy, hydrotherapy, and motor therapy, in his work The Home Handbook of Domestic Hygiene and Rational Medicine, first published in 1881. As he specialized in certain gynecological surgeries (particularly hemorrhoidectomies and ovariotomies) and gastrointestinal surgeries, he developed various instruments for these operations. These included specialized hooks and retractors, a heated operating table, and an aseptic drainage tube used in abdominal surgery. Additionally, Kellogg took keen interest in devising instruments for light therapy, mechanical exercising, proper breathing, and Hydrotherapy. His medical inventions spanned a wide range of applications and included a hot air bath, vibrating chair, oscillomanipulator, window tent for fresh air, pneumograph to graphically represent respiratory habits, loofah mitt, and an apparatus for home sterilization of milk. Some of his inventions were fashionable enough to be included in the first class gymnasium of the RMS Titanic. As in other areas, Dr. Kellogg did not make concerted efforts to profit from his medical inventions. Kellogg's statement in 1916 about his food company sheds light on his general motivations: "I desire to make clear...that the food business I have been carrying on is a part of my general scheme to propagate the ideas of health and biological living. Otherwise, I should not have engaged in it as a commercial enterprise, but I have carried it on as a part of the general philanthropic work in which I was engaged."
John Harvey Kellogg