The safety of the milk produced by growth hormone expressing genetically modified goats was evaluated by administering the milk to SD rats via an oral drip daily for 90 days.Sixty SD rats were divided into three groups according to their sex and weight as follows: the growth hormone-expressing goat milk (GM) group, the normal goat milk (Non-GM) group, and the Saline group.Each rat received lml per 100g of the goat milk or saline, and all rats were fed the same diet and provided with water.The following parameters were evaluated: body weight;growth curve;organ weights;hematological parameters;the serum levels of biochemical markers;immunological parameters including IL-2, IgG, IgE, and IFN-γ;and tissue histopathology.There were no significant changes in the growth curve, organ weights, clinical pathological parameters, immunological parameters, gross necropsy findings and pathology among the three groups.The mean HCT value for female rats in the Non-GM group was a little lower than that of the saline group.However, these data were all in the normal physical range.Overall, no significant treatment-related toxicological changes were observed.