Glutamine has been considered as a dietary supplement with a non-essential amino acid structure. Some studies have found that liver failure may be associated with a high plasma glutamine level. Consumption of this product may be linked to potential adverse effects. This report describes the first case of glutamine-induced hepatotoxicity. A 35-year-old female athlete with severe abdominal pain and scleral icterus was referred to the hospital. She had been taking glutamine powder for the past three weeks. Impaired liver function test and imaging evaluation suggested hepatotoxicity. Glutamine consumption was discontinued and the patient was closely monitored. Finally, after two weeks, the patient recovered successfully. This novel case was the first report regarding glutamine-induced hepatotoxicity. Health care providers must know that consumption of dietary supplements such as glutamine may be associated with serious side effects. Liver damage is a possible side effect of glutamine. Hence it is necessary to consider hepatotoxicity as an adverse reaction in case of glutamine supplement consumption.