vitexagnus castus (Chaste Tree, Chaste Berry, Vitex, Monk's Pepper)

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GENERIC NAME: vitexagnus castus

BRAND NAME: Chaste Tree, Chaste Berry, Vitex, Monk's Pepper

DRUG CLASS AND MECHANISM: Chaste tree is shrub. The dried ripe fruit is used as a natural herbal supplement. Although exact mechanism is not known, Chaste tree presumably works by decreasing follicle-stimulating hormone release. Lowering of follicle-stimulating hormones increases progesterone-to-estrogen ratio, giving relief from menstrual and menopausal symptoms.



PREPARATIONS: Chaste tree is available in crude herb extract capsules, fluid extract, dried fruit extract, and tincture forms.

STORAGE: Due to many manufacturers producing each formulation, storage requirements may vary based individual product.

PRESCRIBED FOR: Chaste tree is used for premenstrual and menopausal symptoms, production of breast milk, female infertility, endometriosis, and acne.


  • Premenstrual syndrome (PMS): Take 4-20mg by mouth per day.
  • Premenstrual dysphoric disorder (PMDD): Take 20-40mg by mouth per day.
  • Crude herb extract: Take 20-240mg by mouth per day, divided in 2 to 3 doses.
  • Fluid extract: Take up to 40 drops by mouth per day.
  • Dried fruit extract: Take 1.6-3ml by mouth up to two times a day.
  • Tincture: Take 35-45 drops by mouth up to three times a day.

The maximum daily dose is 1800 mg per day.

DRUG INTERACTIONS: Chaste tree berry should be avoided in women taking birth control or any other hormonal medications because chaste tree also affects hormone levels.

Chaste tree should be used with caution in certain antipsychotic or anti-Parkinson's medications because chaste tree may affect dopamine levels in brain, reducing the effect of antipsychotic or anti-Parkinson's medications.

PREGNANCY: Chaste tree is known to affect estrogen and progesterone levels, which may not be safe for pregnant women. Therefore, it is not recommended to use chaste tree products in pregnant women.

NURSING MOTHERS: It is not known whether Chaste tree enters breast milk; however, it is best not to use chaste tree in nursing mothers.

SIDE EFFECTS: Side effects of Chaste tree are acne, dizziness, fatigue, stomach upset, headache, agitation, and menstrual changes.

REFERENCE: Stacie E. Geller, et al. Botanical and Dietary Supplements for Menopausal Symptoms: What Works, What Doesn't. J Womens Health (Larchmt). Sep 2005; 14(7): 634–649.

Medically Reviewed by a Doctor on 6/24/2014

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