Semen persicae is the dried mature seeds of Prunus persica (L.) Batsch and P. davidiana (Carr.) Franch and is commonly used in traditional Chinese medicine (TCM) formulations because of its variety of biological effects. The present study aimed to evaluate the antioxidant activity and toxicity profiles of semen persicae extract (SPE) after determining the amygdalin content (4.95%) using HPLC. Regarding the in vitro antioxidant activity, SPE with 2 mg/mL concentration scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and ABTS free radicals with rates of 51.78%, 55.47%, and 57.16%, respectively. The same concentration of SPE chelated 30.76% Fe²⁺. The in vitro cytotoxicity study revealed that SPE induced 92.45% cell viabilities of HEPG2 even at 2000 μg/mL. In the acute toxicity study, oral administration of SPE did not provoke mortality or any toxic signs at doses up to 2000 mg/kg bw. Repeated oral administration for 28 days at doses of 100, 300, and 600 mg/kg per day in rats did not show any toxicity signs or gross pathological abnormalities. The results of the present research provide basic reference data for SPE with a moderate effect on antioxidant activity and low toxicity for future screening of biological and pharmacological properties.