William Donald Kelley (November 1, 1925 – January 30, 2005) was an American orthodontist who developed "non-specific metabolic therapy,"[1] an alternative cancer treatment, now known to be ineffective, which he based on his personal belief that "wrong foods [cause] malignancy to grow, while proper foods [allow] natural body defenses to work.

[4] Kelley formulated his own ideas about cancer, basing them on those of Max Gerson, and named his treatment "non-specific metabolic therapy".

[3] His treatment involves injection of pancreatic enzymes, 50 daily vitamins and minerals, regular administration of laetrile, frequent body shampoos, detoxication using coffee enemas, and a specific diet.

"[2] In 1980, Kelley's most famous patient, Steve McQueen, came to him with a case of inoperable mesothelioma that had not responded to mainstream treatment.

"[4] According to the center, "findings from a study involving patients with inoperable pancreatic cancer showed a decrease in overall survival and poorer quality of life [...] compared to standard gemcitabine-based chemotherapy.