Topical prevention of poison ivy/oak dermatitis.

An organoclay preparation was evaluated for topical protection against experimental poison ivy/oak in a rigorous double-blind study. By direct comparison with the same subject, it proved more effective than comparable preparations of bentonite, kaolin, or silicone in 16 of 17 trials. When evaluated globally against control responses to urushiol the organoclay preparation gave 95.3% protection against topical urushiol applications, ranging from 4.75 to 0.0475 nmol. Bentonite, kaolin, and silicone gave 29.6%, 37.9%, and 32.9% protection, respectively, in the same system. We conclude that organoclay is an effective topical protectant against experimental poison ivy/oak dermatitis, and deserves further clinical evaluation.