Black Haw
A uterine antispasmodic whose entire human record consists of 19th-century clinical reports. Nothing resembling a controlled trial has been published in the modern era.
Evidence last reviewed: August 2026
What the science says
- Uterine cramping Limited evidence
The published human accounts of Viburnum prunifolium for uterine pain and threatened miscarriage are case reports from the 1880s and 1890s. No randomized or placebo-controlled trial exists.
- Plausible mechanism Limited evidence
A pharmacology review of botanicals for women's health lists black haw among traditional uterine relaxants and notes that its activity has been characterized only in preclinical work, with no clinical efficacy data.
Dosage & safety
Studied doseNo studied dose. Traditional preparations use 1-2 g of dried root bark as a decoction, or 5 ml of tincture, up to three times daily.
SafetyContains salicin and oxalates; avoid with aspirin allergy and use caution with a history of kidney stones or anticoagulant use. Historically taken in pregnancy, but with no modern safety data it should be avoided there.
Scientific references
Where to buy
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