11 common herbal topical medicaments in Hong Kong were selected for patch testing to study whether they could cause skin reactions under occlusive conditions. These included White Flower Oil, Hung Far Oil, Kwan Loong Medicated Oil, Tiger Oil, Jaminton Oil, Bee Brand Oil, Tiger Balm, Au Kah Chuen Skin Lotions, Mopiko Ointment, OronineH Ointment and Mentholatum. The former 7 were traditional Chinese herbal medicaments, the last one was made in USA and the remaining 2 were Japanese products. 20 patients were patch tested with the 11 medicaments. Hung Far Oil caused mild to moderately severe irritation in 8 patients; White Flower Oil, Jaminton Oil and Tiger Balm caused mild irritation in 1 to 3 patients; and the rest showed no positive reactions at all. With the exception of Hung Far Oil, all the other medicaments should be safe when applied openly. For Hung Far Oil, additional warning as to its irritant properties and the proper method for its application should be provided for the protection of its users.