The influence of dermal application of sulphur mustard (SM) on hepatic lipid peroxidation and the protective effect of flavonoids in SM toxicity was investigated. SM applied on the skin of mice (0.25 or 0.5 LD50) depleted glutathione (GSH) in blood and liver. Malondialdehyde (MDA) levels in the liver showed an increase indicating lipid peroxidation. Administration of vitamin E or two flavonoids, gossypin (GN) and hydroxyethyl rutosides (HR) after dermal application of SM did not alter depletion of GSH but did reduce the MDA level significantly. Survival time of mice with 1 LD50 SM applied dermally was increased by GN and HR to a greater extent than by vitamin E or sodium thiosulphate probably due to one or more of the analgesic, anti-inflammatory, antihepatotoxic, antihistaminic, mast cell stabilization, lipid peroxidation inhibitory and free radical scavenging actions of the flavonoids. The present study indicates that dermally applied SM can induce lipid peroxidation and GSH depletion, and flavonoids may be beneficial in reducing the toxicity.