Chaste tree berry has been a very important plant for premenstrual syndrome (PMS) and premenstrual dysphoric disorder. There are numerous studies that demonstrate this, and I have reported previously on the use of chaste tree berry for PMS. A very specific PMS use for chaste tree is for cyclical mastalgia, also called premenstrual breast pain/tender/lumpiness.
The evidence for the use of chaste tree berry in the treatment of mastalgia has been reported in both randomized and non-randomized studies. A large open study without a control group of 1634 women with cyclic mastalgia as part of their premenstrual syndrome demonstrated that after 3 months of treatment, 80% of patients rated their response as a good and 81% rates it as a very good treatment for their mastalgia.  In a prospective, multi-center trial using chaste tree in 50 patients with premenstrual cyclic mastalgia, 43 women were treated daily with chaste tree for three consecutive menstrual cycles. By the end of the study period, cyclical mastalgia decreased significantly along with a smaller degree of improvement even 3 months after stopping the plant. Thirty-eight women rated the effectiveness as moderate to excellent, with 5 reporting no effect. In a randomized controlled trial, 97 women with cyclical mastalgia had twice the decrease in intensity of pain after one or two treatment cycles as compared to placebo. The duration of pain also improved in the chaste tree group. In the chaste tree group, half the women did not have severe pain at all during any time of the menstrual cycle and only 25% had severe pain for 4% of the days compared with severe mastalgia one fifth of the time before their use of chaste tree began. In a randomized trial of premenstrual dysphoric disorder, comparing chaste tree with an SSRI, 58% of patients being treated with chaste tree had an improvement in their cyclical mastalgia and 68% of patients had improvements in their psychological symptoms. In a randomized controlled placebo controlled trial, 170 women were given chaste tree or placebo for three consecutive cycles. The improvement in breast pain was greater in the chaste tree group (52%) compared with the placebo group (24%). 
Consider a standardized extract of chaste tree berry—usually one capsule per day all month long for a minimum of two but preferably three consecutive months.
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