Chaste Tree (Vitex agnus-castus)
An ancient Mediterranean remedy with real, modest modern evidence
Evidence grade 3 of 5, Mixed. Read how the Atlas grades evidence.
For PMS the evidence reaches moderate RCT level: Schellenberg's 2001 BMJ trial (Ze 440, n=170) and multiple later placebo-controlled trials feed meta-analyses (Csupor 2019; Verkaik 2017 AJOG) that report a benefit, but reviewers flag high risk of bias, heterogeneity, and likely publication bias, so the effect is probably overstated. Cyclic mastalgia has consistent smaller RCTs (Halaska 1999; a 2019 meta-analysis in J Womens Health), while PMDD, fertility, and menopause rest on weaker or mixed data, so the grade sits at 3 for PMS and lower for the rest.
Reference only. Not medical advice.
What can go wrong
It is generally well tolerated, but because it acts on hormones it should be used cautiously with hormonal medications, in pregnancy, and in hormone-sensitive conditions, and it is best used with medical guidance rather than assumed harmless.
This is something to take to a clinician. The Atlas can tell you what is known about chaste tree (vitex agnus-castus) in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
Chaste tree has been used for women's complaints since ancient Greece, and unusually for a traditional remedy, modern trials give it reasonable support for PMS and cyclical breast pain.
How it is supposed to work
Chaste tree appears to act on the pituitary gland, gently lowering prolactin and shifting the balance of cycle hormones, which is a plausible route to easing premenstrual and breast symptoms. The exact active compounds are not fully pinned down.
Safety in detail
Chaste tree is generally well tolerated over the short term, with mild nausea, stomach upset, headache, or itching reported. Because it acts on the pituitary and lowers prolactin through dopamine pathways, it should be avoided in pregnancy and breastfeeding, avoided in hormone-sensitive conditions such as breast, uterine, or ovarian cancer, and used cautiously with dopaminergic drugs, dopamine antagonists such as some antipsychotics and metoclopramide, and hormonal medicines including oral contraceptives, so use it with medical guidance rather than as an assumed-harmless supplement.
What people get wrong
Often saidHerbal means it does nothing.
ActuallyChaste tree has several supportive trials for PMS and breast pain, better evidence than most traditional remedies.
Often saidHerbal means it is automatically safe.
ActuallyIt acts on the hormonal system, so it can interact with hormonal medications and is not advised in pregnancy.
Who profits, and who pushes back
Herbal-medicine researchers
Find reasonable trial support for chaste tree in PMS and cyclical breast pain, with more research welcome.
European regulators
License certain chaste tree products as medicines for premenstrual complaints.
Where the research comes from
Most of the published research on this comes from one place. 92% of it is from Mediterranean (origin). Findings that no unrelated group has reproduced are weaker than the study count makes them look.
| Place | Share of published research |
|---|---|
| Mediterranean (origin) | 92% |
| Europe | 84% |
| Global supplement market | 78% |
How we got here
Chaste tree is native to the Mediterranean and the western Asian coast, and its use for women's menstrual and breast complaints is recorded in the 1st century CE by Dioscorides in De Materia Medica, with mentions also in Hippocratic writings and Theophrastus. The Greek names agnos and lygos, tied to ideas of purity, blurred into the Latin agnus castus and the reputation for damping sexual desire, so medieval European monasteries used the peppery fruit as a spice believed to support celibacy, which is the origin of the name monk's pepper. From European herbal tradition it moved into modern phytomedicine, and from the 1990s onward standardized extracts such as Ze 440 and BNO 1095 were tested in randomized trials and licensed as medicines in parts of Europe for premenstrual complaints.
Used since antiquity for women's complaints and carried through European herbal tradition, chaste tree is one of the few such remedies that modern trials have partly borne out, which is why it sits at the honest middle of the evidence.
- Ancient GreeceDescribed by Hippocrates and Dioscorides
- Medieval-early modern EuropeCarried through herbal tradition
- 1990s-2020sRandomized trials support PMS and breast-pain use
How it is understood
Today chaste tree, often sold as Vitex, is one of the more evidence-supported herbal remedies for premenstrual symptoms and cyclical breast pain, and it is widely used in Europe, where some formulations are regulated as medicines.
At a glance
- Origin
- Mediterranean, ancient Greece
- Best evidence
- PMS and cyclical breast pain
- Likely action
- Lowering prolactin via the pituitary
- Regulatory note
- A licensed medicine in parts of Europe
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Chaste Tree (Vitex agnus-castus). A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
- What people take it for. We have not catalogued the claims made for it.
Sources
Landmark placebo-controlled RCT: agnus castus fruit extract Ze 440 improved five of six PMS symptoms over three cycles versus placebo (n=170)
Meta-analysis of RCTs finds Vitex agnus-castus superior to placebo for PMS but rates evidence quality low with publication-bias and heterogeneity concerns
Meta-analysis of double-blind RCTs shows a large pooled PMS effect but warns high bias risk and publication bias mean the real effect is likely overestimated
Systematic review of clinical trials for female reproductive disorders: most PMS/mastalgia/hyperprolactinaemia trials favor Vitex but methodological limits remain
Double-blind placebo-controlled RCT: Vitex extract reduced cyclical breast pain intensity faster than placebo with lowered serum prolactin (n=97)
Systematic review and meta-analysis concludes Vitex agnus-castus reduces cyclic mastalgia versus placebo
Vitex Agnus-Castus for Cyclic Mastalgia, Journal of Women's Health 2019
Single-blind RCT in PMDD (n=41): Vitex and fluoxetine had comparable response rates, with fluoxetine better for psychological and Vitex for physical symptoms
NIH authority: evidence for PMS and breast tenderness is suggestive but limited; generally well tolerated short term; unsafe in hormone-sensitive cancers and may be unsafe in pregnancy and breastfeeding; check interactions with a provider
NCCIH (US National Center for Complementary and Integrative Health), Chasteberry
Receptor pharmacology: Ze 440 diterpenes and triterpenes bind the dopamine D2 receptor, the proposed route to lowering prolactin via the pituitary
Diterpene and Triterpene Interactions with Dopamine D2 Receptor (Ze 440), NCBI/PMC
Historical use recorded by Dioscorides for women's complaints; agnos/castus etymology and monastic monk's pepper libido-suppressing tradition
Vitex agnus-castus L.: Main Features and Nutraceutical Perspectives, Forests (MDPI) 2020
Regulatory safety guidance: caution with hormonal and dopaminergic medicines including oral contraceptives; theoretical interference with dopamine antagonists
Therapeutic Goods Administration (Australia), Vitex agnus-castus safety