{"entity":{"id":"chasteberry","kind":"technology","name":"Chasteberry","aka":["Vitex agnus-castus","Chaste tree","Monk's pepper"],"tldr":"Chasteberry is used for premenstrual symptoms and breast pain, with some trial support for premenstrual symptoms. Combined with St John's wort it did not help menopausal symptoms. It has plant hormone activity and in laboratory studies may weaken hormone therapies, so people with hormone-sensitive cancers should ask their team first.","summary":"Chasteberry fruit is said to normalise the menstrual cycle through dopaminergic and progestin-like actions. Memorial Sloan Kettering's About Herbs entry reports clinical studies suggesting it reduces premenstrual symptoms, with a systematic review calling for better-designed trials, preliminary data for breast pain, and no benefit for menopausal symptoms when combined with St John's wort. Because it has phytoestrogenic properties, MSK advises people with hormone-sensitive cancers to consult their physicians, and it should be avoided in pregnancy and breastfeeding. Preclinical studies suggest it may decrease the effects of hormonal therapies and contraceptives, may interfere with antipsychotics and dopamine agonists, and inhibits CYP2C19 and CYP3A4 in vitro; the clinical relevance of each is not yet known. Side effects include nausea, headache, digestive upset, menstrual disturbance, acne and rash. Its combination with St John's wort brings in that herb's well-documented interactions with cancer drugs.","status":"phase-2","asOf":"2026-11-04","links":[{"label":"MSK About Herbs: Chasteberry (page last updated 9 December 2021)","url":"https://www.mskcc.org/cancer-care/integrative-medicine/herbs/chasteberry"}],"tags":["complementary","supportive-care","evidence:insufficient"],"related":["evening-primrose-oil","wild-yam-cream","st-johns-wort-interaction"],"cancers":[],"sections":["supportive-care","hormonal"],"technologies":["integrative-oncology","dietary-supplements-treatment-interactions","endocrine-therapy"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":["b-toxicity-qol"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"Diterpenes act on dopamine D2 receptors and lower prolactin; other constituents bind opioid and oestrogen receptors.","strengths":["Some trial support for premenstrual symptoms"],"limitations":["No benefit for menopausal symptoms with St John's wort","Phytoestrogenic; may weaken hormone therapies in preclinical studies","Enzyme and dopamine interactions"]},"route":"/technologies/chasteberry/","neighbours":{"technology":[{"id":"dietary-supplements-treatment-interactions","kind":"technology","name":"Dietary supplements during cancer treatment: interactions and harms","route":"/technologies/dietary-supplements-treatment-interactions/"},{"id":"endocrine-therapy","kind":"technology","name":"Endocrine therapy (SERMs, AIs, SERDs)","route":"/technologies/endocrine-therapy/"},{"id":"evening-primrose-oil","kind":"technology","name":"Evening primrose oil","route":"/technologies/evening-primrose-oil/"},{"id":"integrative-oncology","kind":"technology","name":"Evidence-based integrative oncology","route":"/technologies/integrative-oncology/"},{"id":"st-johns-wort-interaction","kind":"technology","name":"St John's wort: an interaction to avoid","route":"/technologies/st-johns-wort-interaction/"},{"id":"wild-yam-cream","kind":"technology","name":"Wild yam and 'natural progesterone' creams","route":"/technologies/wild-yam-cream/"}],"section":[{"id":"hormonal","kind":"section","name":"Hormonal Therapy","route":"/fronts/hormonal/"},{"id":"supportive-care","kind":"section","name":"Supportive Care & Survivorship","route":"/fronts/supportive-care/"}],"bottleneck":[{"id":"b-toxicity-qol","kind":"bottleneck","name":"Toxicity and quality of life are undervalued","route":"/bottlenecks/b-toxicity-qol/"}]}}