Agnus Castus

Agnus Castus is a tree native to central Asia and the Mediterranean region. It is the fried ripe berries that are used in herbal medicine. Hippocrates, Dioscorides, and Theophrastus mention the use of agnus castus for a wide variety of conditions, including haemorrhage following childbirth and assisting with the “passing of afterbirth”. Decoctions of the fruit and plant were also used in sitz baths for diseases of the uterus. In addition, agnus castus was believed to suppress libido and inspire chastity, which explains one of its common names, chaste tree.

What it does

Agnus castus contains non-hormone compounds which act on the pituitary gland, specifically on the production of luteinizing hormone and is useful for female hormone health. It essentially raises progesterone levels and lowers oestrogen levels which are commonly out of balance and helps regulate the menstrual cycle. Agnus castus also keeps prolactin secretion in check. The ability to decrease mildly elevated prolactin levels may benefit some infertile women as well as some women with breast tenderness associated with premenstrual syndrome (PMS).

Potential Uses

Amenorrhoea Dysmenorrhoea Endometriosis
Female infertility Acne associated with the menstrual cycle Fibrocystic breast disease
Menorrhagia Premenstrual syndrome Pregnancy & postpartum support
Polycystic ovary syndrome

Other information

With its emphasis on long-term balancing of a woman’s hormonal system, agnus castus is not a fast-acting herb and is unlikely to give immediate relief to the discomfort associated with PMS. For premenstrual syndrome, frequent or heavy periods, agnus castus can be used continuously for four to six months.

Infertile women with amenorrhoea (lack of menstruation) can remain on agnus castus for 12 to 18 months, unless pregnancy occurs during treatment.

It can be used to rebalance hormones after pregnancy, but not if you are breastfeeding.


  • Side effects may include minor stomach upset and a mild skin rash with itching.
  • Agnus castus is not recommended for use during pregnancy and should not be used concurrently with hormone therapy (e.g., oestrogen, progesterone).
  • Agnus castus appears to reduce levels of the hormone prolactin, so should be avoided when taking drugs that have the same action eg bromocriptine.
  • Agnus castus should not be used for children under the age of 12.
  • When this article was written there were no other well-known negative drug interactions with Agnus Castus.

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