Fenclozic acid (proposed brand name Myalex) is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic, antipyretic, and anti-inflammatory properties developed in 1960s by ICI Pharmaceuticals. It failed to pass Phase III clinical trial and was withdrawn from clinical development in 1971 due to severe dose-related hepatotoxicity and jaundice in human, despite showing excellent preclinical safety profile and promising clinical efficacy in animal testings. It is considered a classic example of human-specific drug induced liver injury linked to unique metabolic activation in humans.