Objective According to the technical guidelines for non-clinical safety evaluation of pediatric drugs by both domestic and foreign drug regulatory authorities, this study regarding repeated dose toxicity of compound Taraxacum mongolicum extract (CTME) in juvenile rats was performed to provide reference for clinical trials. Methods One hundred and forty-four juvenile Sprague-Dawley rats (postnatal day(PND) 27) were randomly divided into four groups with 18 of each gender per group. The rats were orally administered twice daily with CTME at doses of 0, 1. 2, 3. 8, 12 g / kg for 4 weeks in a dosage volume of 1 mL/ 100 g. Eighty rats were necropsied after the last administration, and the remaining animals were observed for 4 weeks after drug cessation. Test indicators included routine toxicology indexes, growth development, skeletal development, behavioral testing, sex hormones and immune system development. Results In the high dose group, the male juvenile rats slowly grew, reduced food intake and the juvenile rats of both genders demonstrated salivation, some changes in hematology ( decreased red blood cell count and hemoglobin levels, increased numbers and percentage of reticulocytes ), biochemistry ( decreased total carbohydrates, triglycerides and glucose levels ), urine (increased ketones, protein, leukocytes, specific gravity, pH and microalbumin), immunology ( increased spleen weight and coefficient, and increased IgG in male rats), mild extramedullary hematopoiesis in spleen and liver, and mild proliferation of erythroid hematopoietic cells in bone marrow. The influence could be reversed after 4 weeks of withdrawal. There were no obvious toxic effects on sexual development, skeletal development, growth hormone, behavior, memory, ophthalmology, sex hormones, or bone marrow cell morphology. No significant toxic effects were observed in the middle or low dose groups. Conclusions Under these test conditions, the no observed adverse effect level (NOAEL) of CTME in juvenile rats ( PND27 ~ PND54) was 3. 8 g / kg. However, a dose of 12 g / kg resulted in reversible changes in some indexes, with red blood cells being the main toxicity target.