Objective: To evaluate the genetic toxicity of realgar by using Hamster in vivo chromosome aberration test and CHL cells chromosome aberration test. Method: For in vivo chromosome aberration test

hamsters (Phodopus sungorus) were used to realgar suspension at doses of 33.25

66.5

133 mg·kg-1 respectively for 5 days by ig administration. Colchicine was injected intraperitoneally 2 h before sacrificed. Bone marrow cells were taken to prepare chromosome smears. Mitotic index of bone marrow cells and types of chromosome aberration in 100 metaphase cells per animal were observed under the microscope oil lens. For CHL cells chromosome aberration test

realgar extracts were used to cells at final doses of 0.15

0.3

0.6 g·L-1

cultured for 24 h or 48 h. Colchicine was added at 4 h before harvesting and preparing chromosome smears. Mitotic index of CHL cells and types of chromosome aberration in 200 metaphase cells per dose were observed under the microscope oil lens. Result: ① Obvious mitosis inhibition effects were found at doses of 265.0

530.0 mg·kg-1 realgar suspensions in vivo chromosome aberration test

and of 1.2

2.4 g·L-1 final extract concentrations in CHL cell chromosome aberration test. ②Compared with the negative control

the chromosome aberration rates in both in vivo chromosome aberration test and CHL cell chromosome aberration test after administration were statistically significant increased

and had dose-effect relations. The aberration rate was lower in vivo test than in vitro test. ③More chromosome fragments could be found in in vitro test

while no chromosome fragments was found in in vivo test. The difference may be caused by different drug-cell reactions in in vitro and in vivo. Conclusion: ①Realgar can cause chromosome aberrations both in vitro and in vivo

therefore has genotoxicity effect. ②Hamster (P.sungorus) in vivo chromosome aberration test can be used as one of the test battery for evaluating Chinese medicine genotoxicity.