Abstract: OBJECTIVE: To assess toxicities of the air in Chi-nese medicine clinics polluted by moxa-burning smoke due to moxibustion-derived burning products(MBP).METHODS: Both acute and chronic toxicity studies were conducted. For the acute toxicity study, five groups of Wistar rats(n = 16/group, male: female =1∶1) were exposed to five different concentrations(95%, 90%, 85%, 80% and 75%, respectively) of MBP for 2 h. For the chronic toxicity study, another three groups of male rats(n = 21/group) were exposed to MBP in three concentrations(10%, 40%and 70%, respectively) and one control group exposed to clean air 20 min/d for 144 d. Routine examinations were performed and analyzed by analysis of variance and dose-response relationship.RESULTS: In the acute toxicity study, the number of dead rats in the 95%, 90%, 85%, 80% and 75%groups were 16, 13, 7, 6 and 3, respectively, with LD50 of 86.274% after or during the 2 h exposure.In the chronic toxicity study, MBP exposure induced a decline in activity of the rats. Rats in the10% group showed no signs of toxicity, while those in the 40% MBP group showed toxicity effects on the body weights(P < 0.05) and lung. Rats in the70% MBP group also presented with reversible damage in the blood coagulation system(P < 0.05).CONCLUSION: Exposure to 10% MBP, which is equivalent to 27.45 mg/m3, was under the critical threshold for male rats' safety. Exposure to MBP above that limit induced lung damage. MBP in clinics need to be reduced to a safe level with enhanced ventilation.

Key words: Smoke, Moxibustion, Environmental exposure, Toxicity tests