Abstract

The effect of continuous exposure to proprietary rubefacients (Tiger Balm Red and Tiger Balm White), which contain menthol and camphor as well as clove, cajuput and cassia oils, was tested in rabbits. Dermal irritancy was determined by a 21-day continuous-application patch test (0.5 g/patch) and was assessed according to the Draize method of scoring. At the end of the 21-day test period, the skin was also examined histopathologically. In these tests, Tiger Balm Red (which contained 5% cassia oil plus 5% clove oil) caused irritation consisting of erythema, eschar formation and some oedema, to which a degree of tolerance developed. This irritation resulted in hyperkeratosis and sometimes inflammatory changes but no major damage to the skin. Tiger Balm White (no cassia oil and 2% clove oil) was better tolerated and produced less irritation and histological change than either TIger Balm Red or a mixture of commercial waxes similar in composition to the wax base for Tiger Balm Red. None of the treatments produced any signs of systemic toxicity.