Mistletoe might be a timeless excuse for stealing a kiss at Christmas, but Swiss researchers have found a more practical and innovative use for the plant: treating equine sarcoids, the most common skin tumors in horses.

The research team, led by Vincent Gerber, PhD, DVM, Dipl. ACVIM, ECEIM, FVH, of the University of Bern, in Switzerland, tested the effect of mistletoe extract, Viscum album, on 43 horses with sarcoids using either the extract or a saline placebo.

Sarcoids usually are benign and often cause little disruption in a horse's daily life. Under certain circumstances, however, these tumors can be a nuisance and a health risk, not to mention unsightly. If they appear in an area where tack or equipment might rub against them (for example, near the mouth where a bit would rest), they can crack and bleed frequently in addition to causing significant discomfort. Larger masses are even more troublesome, sometimes splitting and becoming infected by flies and maggots.

In an attempt to find a treatment for sarcoids, the scientists gave 1 milliliter of V. album extract (VAE) in increasing concentrations or saline subcutaneously three times a week over 105 days (15 weeks), and they observed 163 tumors closely for one year. The sarcoids partially or completely regressed in 41% of the horses treated with VAE compared to just 14% in the horses receiving saline