Abstract
Herba Epimedii, commonly known as yin yang huo, inyokaku, and horny goat weed, is a traditional Chinese herbal medicine utilized for treating osteoporosis and enhancing libido. Studies conducted in vitro have demonstrated that Herba Epimedii interacts with the enzyme cytochrome P450 3A4 (CYP3A4). This interaction poses a potential risk for drug-drug interactions, particularly with medications metabolized by CYP3A4, such as buprenorphine. This paper presents a case of a patient experiencing exacerbated opioid cravings following the initiation of Herba Epimedii. This is the first reported case supporting this interaction, emphasizing the necessity of screening for alternative medicines in patients undergoing medication-assisted treatments for opioid use disorder.