https://nccih.nih.gov/health/providers/digest/allergies-science?nav=cd#heading2
Butterbur
There is some evidence that butterbur extract can decrease the symptoms associated with seasonal allergies.The Evidence Base
- The evidence base on efficacy of butterbur for seasonal allergies consists of only a few rigorous randomized controlled trials.
Efficacy
- Findings from a 2007 systematic review of six randomized controlled trials suggest that butterbur is superior to placebo or similarly effective compared with nonsedative antihistamines for intermittent allergic rhinitis. However, firm conclusions could not be drawn because of the financial support from the manufacturer of butterbur to three of the large trials reviewed.
- A 2003 review of several modalities used to treat ocular allergies found that in one study of 125 participants, butterbur was just as effective as a commonly used oral antihistamine for itchy eyes.
Safety
- Butterbur may cause allergic reactions in people who are sensitive to plants such as ragweed, chrysanthemums, marigolds, and daisies.
- Raw extracts of this herb contain toxic pyrrolizidine alkaloids, which can cause liver damage and cancer. Extracts of butterbur have been prepared that are almost completely free from these alkaloids. However, no long-term studies of butterbur products have been conducted, including the reduced-alkaloid products, so its long-term safety is unknown.
