Chasteberry (Vitex)
HerbalAlso called · 7 names▾▴
chasteberry, chaste tree, gattilier, monk's pepper, vitex, Vitex agnus-castus, agnus castus
Herbal supplement (menstrual symptoms)
Herbs and supplements are not FDA-approved before sale. About these sources
- Liquid extract
Research strength: 1 / 5
Health Canada's 2024 monograph says not to use chasteberry during pregnancy or while trying to conceive unless a health professional has been consulted. The EMA reports no human pregnancy data, says animal studies are insufficient, and does not recommend use during pregnancy; NCCIH also notes preclinical concern. A 48-rat study found pregnancy outcomes varied by when extract use began; Health Canada cites it. The EMA and other reviewed sources give no trimester-specific human findings. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- Health Canada: Chaste Tree monograph (2024)
- EMA: EU herbal monograph on Vitex agnus-castus fruit, Revision 1EU agencyEuropean guidance
- Najib et al. (2022): Rat pregnancy studyUS government
- NCCIH: ChasteberryUS government
Research strength: 1 / 5
Health Canada's 2024 monograph says not to use chasteberry during pregnancy or while trying to conceive unless a health professional has been consulted. The EMA reports no human pregnancy data, says animal studies are insufficient, and does not recommend use during pregnancy; NCCIH also notes preclinical concern. A 48-rat study found pregnancy outcomes varied by when extract use began; Health Canada cites it. The EMA and other reviewed sources give no trimester-specific human findings. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- Health Canada: Chaste Tree monograph (2024)
- EMA: EU herbal monograph on Vitex agnus-castus fruit, Revision 1EU agencyEuropean guidance
- Najib et al. (2022): Rat pregnancy studyUS government
- NCCIH: ChasteberryUS government
Research strength: 1 / 5
Health Canada's 2024 monograph says not to use chasteberry during pregnancy or while trying to conceive unless a health professional has been consulted. The EMA reports no human pregnancy data, says animal studies are insufficient, and does not recommend use during pregnancy; NCCIH also notes preclinical concern. A 48-rat study found pregnancy outcomes varied by when extract use began; Health Canada cites it. The EMA and other reviewed sources give no trimester-specific human findings. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- Health Canada: Chaste Tree monograph (2024)
- EMA: EU herbal monograph on Vitex agnus-castus fruit, Revision 1EU agencyEuropean guidance
- Najib et al. (2022): Rat pregnancy studyUS government
- NCCIH: ChasteberryUS government
Chasteberry (Vitex) — Breastfeeding
Research strength: 3 / 5
LactMed says no scientifically valid trials support chasteberry to increase milk supply; low doses may raise prolactin, while higher doses might lower it and reduce lactation. Dugoua et al. (2008) report conflicting expert views about whether it increases or decreases milk supply. The EMA says reproductive studies suggest it may affect lactation and does not recommend use while breastfeeding; Health Canada advises consultation before use. NCCIH also notes preclinical concern. LactMed and Dugoua et al. leave the effect in people uncertain. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- LactMed: ChasteberryUS government
- Dugoua et al. (2008): Chastetree during pregnancy and lactationUS government
- EMA: EU herbal monograph on Vitex agnus-castus fruit, Revision 1EU agencyEuropean guidance
- Health Canada: Chaste Tree monograph (2024)
- NCCIH: ChasteberryUS government
Pregnancy
Health Canada's 2024 monograph says not to use chasteberry during pregnancy or while attempting to conceive unless a health professional has been consulted. The EMA states that no data from use in pregnant women are available, animal studies are insufficient for reproductive toxicity, and pregnancy use is not recommended. Najib et al. (2022) tested an alcoholic Vitex fruit extract in 48 rats divided into six groups of eight. Treated groups received 365 mg/kg from insemination or beginning 30 days before pregnancy. The authors report that pregnancy rate and outcome were affected, with timing affecting live birth and abortion rates. This small animal study does not establish human outcomes; no human pregnancy outcome or trimester-specific data were identified in the reviewed sources.
Breastfeeding
LactMed states that no scientifically valid clinical trials support chasteberry as a galactagogue. It says low doses may increase prolactin, while some evidence suggests that high doses may lower prolactin and lactation. The EMA's 2018 monograph says reproductive studies suggest the fruit may affect lactation and that use during lactation is not recommended. Dugoua et al. (2008) report that theoretical and expert opinions conflict about whether chasteberry increases or decreases lactation. LactMed describes older human studies but says their methods do not meet current standards. The available evidence does not establish the direction or size of any effect in people.
Chasteberry is the fruit of Vitex agnus-castus. LactMed lists essential oils, iridoid glycosides, diterpenes, and flavonoids among its compounds.
What was tested
The 2022 pregnancy study was a prospective randomized rat experiment with 48 animals in six groups. It tested an alcoholic fruit extract at 365 mg/kg, started at insemination or 30 days before pregnancy, and assessed pregnancy rate, fetal weight and sex, fetal number, abortion, stillbirth, and estradiol. The results varied by when treatment began. No human pregnancy outcome study was identified in the reviewed sources. LactMed describes historical reports and small studies about lactation, but says no scientifically valid clinical trials support use as a galactagogue.
Does chasteberry increase or decrease breast-milk supply?
- Source A says
- LactMed says low doses may increase prolactin and chasteberry is promoted as a galactagogue, but no scientifically valid clinical trials support this use. It also says high doses may decrease prolactin and lactation. (LactMed: Chasteberry)
- Source B says
- The EMA says reproductive studies suggest the fruit may affect lactation and does not recommend use during lactation. Health Canada's 2024 monograph says not to use during breastfeeding unless a health professional has been consulted. (EMA: EU herbal monograph on Vitex agnus-castus fruit, Revision 1, Health Canada: Chaste Tree monograph (2024))
- Why they differ
- The sources discuss different evidence: dose-related prolactin observations and a proposed milk-supply benefit, theoretical and expert opinions, and reproductive-study findings. They do not establish a consistent human effect.
- Other sources
- Dugoua et al. (2008) report that theoretical and expert opinion conflict about whether chasteberry increases or decreases lactation. (Dugoua et al. (2008): Chastetree during pregnancy and lactation)
- What the evidence shows overall
- The sources do not establish a milk-supply benefit in people. The possibility of reduced lactation is based on reproductive-study findings, while the direction and size of any effect in people remain uncertain.
- Health Canada's 2024 monograph says to consult a health professional before use during pregnancy, breastfeeding, or while attempting to conceive. (Health Canada: Chaste Tree monograph (2024))
General research, not specific to pregnancy.
The EMA page describes certain agnus castus fruit preparations for premenstrual symptoms in adult women; these uses do not establish pregnancy or breastfeeding evidence.
- The EMA says one particular dry extract preparation can be used continuously over 3 months for premenstrual syndrome, while other fruit preparations are used for minor symptoms before a period based on long-standing use. (EMA: Agnus castus fruit summary for the public)
- LactMed: ChasteberryUS governmentSecondaryPage dated 2024-11-15
- NCCIH: ChasteberryUS governmentSecondary
- EMA: EU herbal monograph on Vitex agnus-castus fruit, Revision 1EU agencySecondaryPage dated 2018-03-27Independent checkEuropean guidance
- Health Canada: Chaste Tree monograph (2024)SecondaryPage dated 2024-03-28Independent check
- Najib et al. (2022): Rat pregnancy studyUS governmentPrimary
- Dugoua et al. (2008): Chastetree during pregnancy and lactationUS governmentPrimaryPage dated 2008-01-18Independent check
- EMA: Agnus castus fruit summary for the publicEU agencySecondaryPage dated 2020-02-25European guidance
Last reviewed 2026-10-16
Independent check 2026-10-16
Not yet clinician-reviewed
Ask your provider about your situation.