5-Hydroxy Diclofenac-d5 is deuterium labeled 5-Hydroxy Diclofenac (H825230), which is a metabolite of Diclofenac (D436450), a nonsteroidal anti-inflammatory compound and a cyclooxygenase (COX) inhibitor (1,2,3). Diclofenac exhibits anti-inflammatory, analgesic, and antipyretic properties.