The aim of this study was to evaluate the potential mutagenic effects of ginseng (herbal medicine) on maternally treated postimplanted mouse foetuses. A total of 60 adult albino female mice were used and divided into 6 groups (10 females each). The first group (I) served as a control group and received oral doses of the vehicle (0.5 ml disteled water ) for 60 days before pregnancy to 13th day of pregnancy. The rest 5 groups received orally 4mg/kg.bw of ginseng for 7, 14, 30, 45 and 60 days before day 0 of gestation and extended to 13th day of pregnancy. Then 6 females of each group were sacrificed, feotuses sample from each female were taken and subjected to cytogenetic analysis. The rest females of each group (4 females) were continuously treated and sacrificed at day 17 of getation, foetuses were examined morphologically and for different features such as implanation sites, living feotuses, resorbed foetuses and foetus body weight. Chromosome analysis of the present study (Table 1) revealed that there were numerical aberrations (peridiploidy). There was a difference only between group II and III in respect to hypodiploid (2n-), meanwhile, hyperdiploid (2n+) were more frequent in group IV and VI than that in control group (group I). For the total numerical aberrations, there were significant differences between groups II, VI compared to the control group. All groups had little frequencies of structural aberrations especially for chromatid gaps, breaks and fragments. There were a significant differences between group IV and VI compared with the control group for the deletions. Chromosome breaks were more frequent in the groups III and IV compared to the control group, whereas groups V, VI had more frequencies of centromeric attenuations than the control group. There were no differences between control group and the rest of all groups investigated for implantation sites, living foetuses and resorbed foetuses (Table 2), whereas for gross malformation, 5.41 % of group VI where abnormal and the rest of all groups had no malformations. For the mean fetal body weight, there was a significant difference among the control group (I) and the groups number II, III and VI. We conclude that treatment with ginseng as a herbal medicine may cause fetal chromosomal aberrations as well as gross malformation especially when taken for a long time and extended during pregnancy. So, we recommend that the use of ginseng during first trimester of pregnancy should be with caution.