Which herbal-drug interaction related to reuptake serotonin inhibitors causes an increased risk of serotonin syndrome?

St. John’s Wort is well-documented for its interaction with various medications, particularly selective serotonin reuptake inhibitors (SSRIs). It acts as a natural antidepressant and, when taken alongside SSRIs, can lead to an excessive accumulation of serotonin in the brain, resulting in a potentially life-threatening condition known as serotonin syndrome. This condition is characterized by symptoms like confusion, rapid heart rate, high blood pressure, dilated pupils, and severe agitation.

While Ginkgo Biloba has certain interactions with drugs, particularly anticoagulants, it is not associated with increasing serotonin levels and does not have a known risk for precipitating serotonin syndrome in combination with SSRIs. Reiki, a form of energy healing, does not involve drug interactions and thus is irrelevant in this context. Therefore, the identification of St. John’s Wort as the herbal supplement that poses the risk of serotonin syndrome due to its effects on serotonin levels makes it the most appropriate answer.