Herb library · Herb · Viburnum prunifolium
Black haw
The bark of a small tree of the eastern and southern United States, a close relative of cramp bark, used in the 1800s for menstrual cramps and in pregnancy. It has not been studied in people with modern methods.
Traditional use
King's American Dispensatory (1905) records that Dr. D. L. Phares of Mississippi brought black haw into medicine, and that by 1905 its main use was for cramping, painful periods and an irritable womb, and to try to hold a threatened pregnancy. The same book records something harder: that planters in the South forced enslaved women to drink black haw daily while pregnant, to keep them from ending pregnancies with cotton root.
What studies show
No studies in people of this herb on its own yet. What is known of it comes from the traditions that use it.
- Insufficient
Menstrual cramps and pregnancy: no modern study of black haw in people was found. Lab studies show compounds from the bark relaxing muscle tissue, which does not show what the bark does in people.
Be careful of
Cautions
- PregnancyDo not use it in pregnancy or while breastfeeding. A threatened miscarriage needs urgent medical care; black haw has never been tested for it.
- AmountKing's American Dispensatory (1905) notes that large doses sometimes cause nausea and vomiting.
- NoteBlack haw and cramp bark (Viburnum opulus) are related barks sold for the same uses; check which one a product contains.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child. Severe period pain deserves a clinician's look.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“By Dr. D. L. Phares, of Mississippi, who brought the remedy forward, it was described as having nervine, antispasmodic, tonic, astringent, and diuretic properties.”
“It was for a long time customary for planters to compel their female slaves “to drink an infusion of black haw daily whilst pregnant to prevent abortion, from taking the cotton-root” (Scudder, Spec. Med., 266).”
Sources
- In vitro relaxant and spasmolytic effects of constituents from Viburnum prunifolium and HPLC quantification of the bioactive isolated iridoids (2009) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Botanicals and Their Bioactive Phytochemicals for Women's Health (Pharmacol Rev, 2016) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.