Evaluation of the safety of external application of herbal oil (“Gidan”) on horses’ limbs

Tendons and ligaments injuries are highly common in the equine population and they tend to carry a high recurrence rate and prolonged healing period. The treatment and prevention of tendon injuries is complex and the combination of complementary and alternative methods into current regimes may be beneficial. However, the literature regarding the safety and efficacy of such treatments is scarce. “Gidan” is an herbal liniment, designed according to traditional Chinese methods, for the relief of muscle and tendon related pain. This study aimed to evaluate the safety of external application of “Gidan” on distal limbs of horses and lay the foundation for future studies evaluating the efficacy of “Gidan” and similar materials. “Gidan” was applied twice daily on two distal limbs of 10 horses for a 7 day period. The two remaining limbs served as controls and were treated with a carrier liniment without the “Gidan” herbal extracts. Two limbs of each horse (“Gidan” and control) were bandaged. Allocation to treatments was random. Adverse skin reactions were assessed, ranked and photographed during the trial period and at 5 days following last application. Nearly half of the limbs tested exhibited mild adverse skin reactions, most of them delayed and were only visible days after application was ceased. Analysis shows that bandaging was clearly the main risk factor for developing such reactions. It was concluded that “Gidan” was not the cause of the dermatological reactions. The external topical use of “Gidan” herbal liniment on horses’ distal limbs appeared to be safe on nonbandaged limbs. The use of bandaging requires further evaluation.