MAJOR CHEMICAL CONSTITUENTS

Important compounds in dong quai include alkylphthalides present in the essential oil fractions of the plant and ferulic acid. The plant also contains additional essential oils, amino acids, lipids, aromatic compounds, polysaccharides, monoterpenes, and diterpenes. Vitamins A, B₁, B₁₂, E, biotin, and nicotinic acid, as well as a number of trace minerals, are found in the root.

PRINCIPAL GYNECOLOGIC AND OBSTETRIC USES

TRADITIONAL AND HISTORICAL USES

Dong quai is one of the oldest and most respected herbs in the Chinese pharmacopoeia, used since at least the first century to “nourish the blood and qi” and restore a state of well-being. Although not used exclusively for gynecologic complaints, its popularity as a woman’s herb in the Western world stems from its traditional Chinese medicine (TCM) uses for the treatment of dysmenorrhea, amenorrhea, other menstrual irregularities, and uterine complaints. Traditionally, the herb is not used alone, but in combination formulae specific to various conditions. In addition to the aforementioned indications, it was used in pregnancy formulae to “quiet the fetus” in cases of threatened miscarriage, and in the postnatal period in soups to strengthen the blood and restore strength; however, in the West it is typically contraindicated during pregnancy (see Use in Pregnancy and Lactation).

CLINICAL INDICATIONS

Dong quai is a popular herb in contemporary western herbal medicine used in the treatment of a variety of gynecologic complaints, particularly for menstrual irregularities and endometriosis. Herbalists consider dong quai a “uterine tonic” based on its traditional uses and also on in vivo and in vitro animal studies demonstrating

Dong quai (Angelica sinensis).

(Photo by Martin Wall.)

both stimulating and relaxing activity on uterine tissue. Its reported efficacy in the treatment of dysmenorrhea and endometriosis most likely lies in its effects as an anti-inflammatory, antispasmodic, and analgesic. It is also thought to improve blood flow generally, specifically in the pelvis; thus it is used to relieve pelvic congestion syndrome and associated pelvic pain and uterine fibroids, which some herbalists consider associated with pelvic congestion and poor uterine circulation. Although it is sometimes touted as an herb for perimenopausal symptoms, alone it is traditionally considered a “heating” herb, which would actually exacerbate symptoms such as night sweats, hot flashes, irritability, and insomnia. However, in TCM these symptoms are also associated with yin and blood deficiency; thus in appropriately combined formulas, it can be used for the treatment of perimenopausal complaints.

IN VITRO, ANIMAL, AND CLINICAL DATA

Few studies have been done with dong quai as a single agent looking at its effects on gynecologic conditions for which it is traditionally indicated and for which modern herbal practitioners often use it. Further, many of the studies that have been done looking at dong quai are not in English language journals, limiting review of the literature and also raising questions about the standards used for clinical studies. Limited preclinical trials and human studies have shown efficacy in the treatment of dysmenorrhea and infertility resulting from tubal occlusion. Questions have arisen about whether dong quai has estrogenic effects. To date this has not been determined, with one clinical trial of 71 symptomatic perimenopausal women showing no significant changes in vaginal cell maturation or endometrial thickness after 24 weeks of a daily dose of 4.5 g of crude herb; however, a longer trial may be needed to demonstrate changes in vaginal and epithelial tissue. Numerous preclinical trials have demonstrated the herb’s dual ability to both relax and stimulate uterine smooth muscle. Dong quai has been shown to relax the vascular smooth muscle as well as uterine and intestinal smooth muscle, which may support its role in alleviating the symptoms of dysmenorrhea and endometriosis. Its stimulating effect is not usually corroborated with a clinical condition, but may explain its popularity as a uterine tonic for uterine atony and “boggy” uterus associated with uterine fibroids. Pharmacologic studies in animals suggest that dong quai may exert effects on the cardiovascular system, including increased myocardial perfusion, decreased myocardial oxygen consumption, increased blood flow, decreased afterload, inhibition of platelet aggregation, and inhibition of arrhythmias. Human clinical evidence suggesting hypotensive and cardiovascular protective effects of dong quai, however, is weak, with numerous methodologic flaws. Limited evidence suggests that the herb may have hemorrhologic effects, including decreased platelet aggregation and increased PT time.

MECHANISMS OF ACTION

The mechanisms of action for this herb are poorly elucidated. It is thought that the volatile components of the oil may be responsible for the uterine and other smooth muscle spasmolytic effects, whereas the nonvolatile components are excitatory. The spasmolytic effects may result from histamine receptor blocking activity and calcium ion channel effects of the phthalides; however, this has not been fully determined.

RATINGS

The editor’s note in the BSH states that both stimulating and relaxing effects on the uterus have been reported for this herb, but that no contraindication during pregnancy is noted in any of the authoritative reference books used in compiling the BSH. Canadian regulations require a bilingual label warning against dong quai use during pregnancy.

PREPARATIONS USED CLINICALLY

DOSAGE

SAFETY INFORMATION: HERB DRUG INTERACTIONS, TOXICITY, AND CONTRAINDICATIONS

Dong quai is associated with few side effects and a high level of safety in the general literature. In a survey conducted by the American Herbalists’ Guild of its professional membership, 44% of those who responded reported having observed side effects, including worsening of endometriosis, bleeding gums with prolonged use over months, increased and sometimes excessive menstrual flow, breast tenderness, headaches, and irritability. All side effects are reversible with discontinuation of use. The increased bleeding seen with use of the herb is predictable given clinical studies demonstrating decreased platelet aggregation and increased PT time. Because of these effects, dong quai is contraindicated prior to surgery, with most practitioners suggesting a 2-week holiday from the herb prior to major procedures. The herb is also theoretically contraindicated for use in conjunction with anticoagulant medical therapy, i.e., warfarin.

USE IN PREGNANCY AND LACTATION

In spite of customary use in TCM formulae for miscarriage prevention, dong quai is generally considered contraindicated in all trimesters of pregnancy because of possible anticoagulant and uterotonic effects. The BSH states that it is not to be used during pregnancy unless otherwise directed by an expert qualified in its use. Anecdotal reports suggest that solo administration of the herb during pregnancy may be associated with miscarriage. Data regarding fetotoxicity, mutagenicity, and teratogenicity are lacking. Personal experience, including challenge and re-challenge in three nursing mothers has suggested that consumption of dong quai decoctions in formulae by lactating mothers may lead to a rash in the newborn.

Dong quai is clinically associated with increased bleeding. Herbalists typically contraindicate its use during the menses, during pregnancy, in cases of abnormal uterine bleeding, and in conjunction with anticoagulant medications. It is also typically contraindicated in pregnancy because of possible uterine stimulatory effects; however, it is used in TCM in customary formulations to prevent miscarriage. It has been seen to cause skin rash in the infant of nursing mothers consuming the decocted herb in the neonatal period.