Chastetree (Vitex agnus-castus), also known as chasteberry, has been traditionally used to manage various menstrual disorders, including premenstrual syndrome (PMS). Specifically, for PMS Type S (where "S" stands for "Sugar Craving", but also often associated with symptoms like irritability and mood swings, thought to be related to serotonin and hormonal fluctuations), there is notable scientific evidence supporting its efficacy. Multiple randomized, placebo-controlled trials and meta-analyses have found that extracts of Vitex agnus-castus significantly reduce overall PMS symptoms, including mood disturbances, breast tenderness, and cravings. The proposed mechanism involves modulation of prolactin secretion via dopaminergic activity, which can help stabilize hormonal fluctuations implicated in PMS symptoms. Key studies, including those cited by the Cochrane Database (2012) and other systematic reviews, suggest that chasteberry is superior to placebo for the relief of PMS symptoms, with a favorable safety profile. However, while the evidence is robust for general PMS, most studies do not explicitly break down efficacy by subtypes such as "Type S". Nevertheless, given the overlap in symptom relief and the known mechanisms, chasteberry is scientifically validated as a supportive treatment for PMS, including subtypes characterized by mood and craving symptoms.