Abstract: Objective To test the in vitro effect of the extract of Herba taraxaci on Demodex folliculorum. Methods Active Demodex folliculorum were obtained from patients with moderate to severe demodex infestation. Herba taraxaci and Radix stemonae were extracted respectively with 80% ethanol under 85℃， and a preparation with a concentration of 200mg/ml was made. The extractions were used in vitro to examine the anti-mite activity by observing time of killing mites. Physiological saline and Radix stemonae extraction served as blank control and positive control respectively.PH value of Herba Taraxaci extract was noted. Skin irritation test of normal and wounded skin and acute toxicity test were carried out with rabbit shin, and Herba taraxaci and 75% ethanol were served as experiment and control medicine. Results Motion and morphology of the mites considerably changed with the effect of Herba taraxaci extract. The time of mite-killing was （1.50±0.65）min with Herba taraxaci and （3.53±1.04）min with Radix stemonae respectively （P＜0.01） and over 120 min with physiological saline. pH value of Herba taraxaci extract was 5.00±0.28. Score for irritation to normal and wounded rabbit skin was 0 and 0.3 respectively， and acute toxicity test showed no significant toxicity. Conclusion Herba taraxaci extract shows a remarkable in vitro activity to Demodex folliculorum with skin safety.

Key words: Herba taraxaci, Demodex folliculorum, Traditional Chinese medicine, Anti-mite