目的：检测过氧化氢（Ｈ２Ｏ２）、甲磺酸乙酯（ＥＭＳ）、丝裂霉素Ｃ（ＭＭＣ）、二甲基亚硝胺（ＤＭＮＡ）、苯并（ａ）芘（ＢａＰ）、２氨基芴（２ＡＦ）和环磷酰胺（ＣＰ）诱发小鼠、大鼠及人外周血淋巴细胞ＤＮＡ单链断裂．方法：体外单细胞微量凝胶碱性电泳试验（慧星试验）．结果：除ＥＭＳ０９７ｍｍｏｌ·Ｌ－１在小鼠淋巴细胞，ＭＭＣ３０μｍｏｌ·Ｌ－１在小鼠、人淋巴细胞中呈阴性外，其余均为阳性．最低可检测浓度分别为Ｈ２Ｏ２１μｍｏｌ·Ｌ－１，ＥＭＳ０４８ｍｍｏｌ·Ｌ－１，ＢａＰ５０μｍｏｌ·Ｌ－１，ＣＰ２０ｍｍｏｌ·Ｌ－１，ＭＭＣ１０μｍｏｌ·Ｌ－１，ＤＭＮＡ２７３ｍｍｏｌ·Ｌ－１，２ＡＦ６２５μｍｏｌ·Ｌ－１．ＣＰ、ＢａＰ、２ＡＦ需经Ｓ９Ｍｉｘ代谢活化才显示毒性．结论：彗星试验检测出ＭＭＣ诱导大鼠，ＥＭＳ诱导大鼠和人，以及Ｈ２Ｏ２、ＤＭＮＡ、ＢａＰ、ＣＰ和２ＡＦ诱导小鼠、大鼠和人外周血淋巴细胞ＤＮＡ单链断裂损伤． Objective: To detect the effects of hydrogen peroxide (H2O2), ethyl methanesulfonate (EMS), mitomycin C (MMC), dimethylnitrosamine (DMNA), benzo (a) Aminofluorene (2  AF) and cyclophosphamide (CP) induced mouse, rat and human peripheral blood lymphocyte DNA single strand breaks. Methods: In vitro single-cell microgel gel electrophoresis (Comet test). RESULTS: Except EMS097mmol·L-1 in mouse lymphocytes and MMC30μmol·L-1 in mice and human lymphocytes, the others were all positive. The lowest detectable concentrations were H2O21μmol·L-1, EMS048mmol·L-1, BaP50μmol·L-1, CP20mmol·L-1, MMC10μmol·L-1, DMNA273mmol·L-1, 2  AF62  5μmol·L-1. CP, BaP, 2  AF required by the S9Mix metabolic activation showed toxicity. Conclusion: Comet assay detected MMC-induced rat, EMS-induced rat and human, as well as H2O2, DMNA, BaP, CP and 2  AF induced DNA, single strand breaks in mouse, rat and human peripheral blood lymphocytes.