Benefits
Traditional Chinese herb for menstrual comfort and blood support
In traditional Chinese medicine dong quai root is used to enrich the blood, support circulation, regulate the menstrual cycle and ease cramping, usually within multi-herb formulas. A European regulatory review found no data explaining the cycle-regulating use, and no placebo-controlled trials have tested it for premenstrual complaints.
Tested alone against placebo for menopausal hot flashes
In a 24-week double-blind trial in 71 postmenopausal women, dong quai alone did no better than placebo for hot flash counts or the Kupperman symptom index. A small 3-month placebo-controlled trial in men with hot flashes from androgen deprivation therapy also found no difference in frequency, severity or duration.
Estrogen-like activity tested in lab and human studies
Lab results conflict: some extracts acted on estrogen-sensitive cells while others showed no receptor binding, and no estrogenic compound has been isolated. In the 24-week human trial, dong quai alone did not differ from placebo in endometrial thickness or vaginal cell maturation.
Studied with chamomile in a two-herb blend (Climex)
In a 12-week placebo-controlled trial in 55 postmenopausal women, a chewable blend of 375 mg dong quai and 150 mg chamomile a day was reported to cut hot flush number and intensity more than placebo. The stated analysis compared each group only with its own baseline, 45 women were analyzed, and the effect cannot be split between the two herbs.
Ingredient in the Chinese formula Dang Gui Buxue Tang
Dang Gui Buxue Tang pairs 1 part dong quai with 5 parts astragalus, so astragalus is the main herb. In a 6-month placebo-controlled trial in 100 women it showed no overall difference from placebo for hot flushes, beating placebo only for mild flushes. A later dose-ranging trial had no placebo arm.
Platelet and clotting tests in healthy volunteers
In a 3-week randomized placebo-controlled study, dong quai did not change PT, APTT or thrombin generation in healthy adults, and adding it to aspirin did not deepen aspirin's platelet inhibition; 2 of 24 people showed reduced platelet response to one test agent. The study does not address use with warfarin.
Mechanism of action
Ferulic acid and antiplatelet activity
Ferulic acid and other water-soluble compounds in the root are thought to underlie anti-inflammatory, antiplatelet and antithrombotic effects seen in animal models. The root also contains coumarin derivatives, which reviewers consider the likely reason for reported interactions with warfarin.
Z-ligustilide and smooth muscle relaxation
Z-ligustilide, a main component of the essential oil, inhibited contractions of isolated rat uterus in a dose-dependent way and improved microcirculation in lab studies. It is unstable and poorly absorbed after oral intake, which may limit these effects in people.
Unsettled estrogen receptor activity
Studies of estrogen activity disagree: some extracts stimulated estrogen-sensitive breast cancer cells and an ethanol extract raised uterine weight in rats, while methanol extracts showed no estrogen receptor binding and another extract caused no uterine growth in mice. No purified estrogenic compound has been identified.
Anti-inflammatory activity in lab models
Z-ligustilide and lipophilic dong quai extracts lowered nitric oxide, TNF-alpha and other inflammatory signals in macrophage cell studies, and the volatile oil reduced acute inflammation in a rat model. These effects have not been tested as outcomes in human trials.
Clinical trials
Double-blind randomized placebo-controlled trial of dong quai alone in postmenopausal women with hot flashes. Outcomes were endometrial thickness by ultrasound, vaginal maturation index, the Kupperman index and a hot flash diary; all were null. The 4.5 g a day dose is reported in a later review (Dietz et al. 2016), not in the abstract; PubMed lists non-US government support (Hirata et al. 1997, Fertil Steril)
71 adults (mean age 52.4) with FSH above 30 mIU/mL who had flushing, randomized to dong quai or placebo for 24 weeks.
No statistically significant differences between groups in endometrial thickness, cell maturation index, number of flushing episodes or the Kupperman index. The authors concluded that dong quai used alone produced no hormone-like response and was no more helpful than placebo for symptom relief.
Small double-blind randomized placebo-controlled pilot trial for hot flashes in men on androgen deprivation therapy; the primary result was null. Tablets held 500 mg of dong quai (Swiss Herbal Remedies) and the placebo was made by the hospital pharmacy; the authors declared no competing interests (Al-Bareeq et al. 2010, Can Urol Assoc J)
22 men receiving LHRH agonist therapy for prostate cancer with bothersome flushing, randomized 1:1 to daily dong quai or placebo for 3 months; 17 completed.
No significant differences between groups in the severity, frequency or duration of flushing. The dong quai group started with more daily episodes (p = 0.02) and had a slight, nonsignificant decrease. INR and partial thromboplastin time were normal at baseline and follow-up in all patients, and no bleeding problems occurred during the study.
Randomized placebo-controlled trial of Climex chewable tablets, each with 75 mg Angelica sinensis and 30 mg Matricaria chamomilla, in postmenopausal women with hot flushes; dong quai is the larger share by weight. Placebo tablets looked identical, blinding was not otherwise described, and funding is not stated. The statistics section describes only within-group paired t-tests, with women serving as their own controls, so the reported group difference is not backed by a described between-group test; the result is not credited to dong quai (Kupfersztain et al. 2003, Clin Exp Obstet Gynecol)
55 adults aged 45 to 65 who declined hormone therapy, taking 5 chewable blend tablets daily (375 mg dong quai plus 150 mg chamomile) or placebo for 12 weeks; 45 were analyzed (22 blend, 23 placebo).
The authors reported reductions of 90 to 96% with the blend vs 15 to 25% with placebo in flushing number and intensity (p < 0.001), less sleep disturbance and fatigue, and minor nonspecific adverse effects in three people. Because both herbs were given together and the analysis was within each group, the effect cannot be assigned to dong quai.
Randomized double-blind placebo-controlled study of three herbs; each subject went through 3-week phases of herb alone, aspirin alone and aspirin with herb, separated by 2-week washouts. Dose is not given in the abstract (Fung et al. 2017, Phytomedicine)
Healthy volunteers, 25 enrolled per herb; 24 analyzed in the Angelica sinensis arm.
Dong quai did not change PT, APTT or thrombin generation. Two of 24 people showed reduced arachidonic acid induced platelet aggregation, with no effect on other agonists. Adding dong quai to aspirin did not further increase platelet inhibition, and no significant bleeding was recorded. The study did not test use with warfarin.