After some time, with new management and new policies, the name was changed from the Health Reform Institution to the Sanitarium. Radical improvements in equipment, establishment of training school for nurses, and scientifically trained physicians built confidence in the organization and won favor with the public leading to the dedication
of a new building in 1877. In 1902, a devastating fire burned down the main building and the hospital but it was replaced by a modern building structure which was completely fire proof. Some years later, more structures were added to the building consisting of 6 floors filled with hospital beds, guest rooms, gymnasiums, spas, research labs, operating rooms, and other physical exercise rooms laced with equipment.
The Smiths saw it necessary to hire a trained Medical professional to run the Sanitarium effectively with the growing number of patients. Dr John Kellogg was appointed Medical Director of the Sanitarium, his term stretching over 67 years, until his death. During his leadership the Sanitarium was split from the administration of the church after he decided to refine and improve the water therapy treatments, add more scientifically based treatments, revise the diet of the patients and hire professionally trained staff. In 1942, a fall in the economic wealth of the local citizens lead to a decline in patients, forcing Dr Kellogg to move the Sanitarium to smaller quarters. The Sanitarium survived through it all.
The next year Dr Kellogg died (1943) but the Sanitarium continued to thrive, eventually falling back under the ownership and control of the church. During the next decade the concentration of treatments changed from medical treatment to psychiatric and substance abuse treatment.