ABSTRACT: The ethanolic extract of Prunus mume (EPM) is a novel polyphenol preparation derived from branches (with leaves) of Prunus mume, which could be used as a functional ingredient for antioxidant and antiobesity therapy. The purpose of this study was to evaluate the safety of EPM. An EPM was prepared and evaluated for oral acute and subacute toxicity in Sprague–Dawley rats, while its mutagenic potential was assessed by a reverse mutation test using Salmonella typhimurium, by a bone marrow cell micronucleus test using ICR mice, and by a sperm abnormality test using ICR mice. The results showed no acute lethal effects at the maximal tested EPM dose of 20 g/kg bw in either rats or mice, suggesting that EPM can be regarded as virtually nontoxic. Administration at levels of 0.84, 1.67, and 3.33 g/kg bw to rats for 30 d did not induce any significant hematological, clinical, chemical, or histopathological changes. No mutagenicity evidence was detected in any of the 3 mutagenic tests. The level of “no observed adverse effect” (NOAEL) for EPM was above 3.33 g/kg bw for the subacute toxicity study.