摘要Objective: To determine the anti-breast cancer activities and the safety oral consumption of Dillenia suffruticosa root aqueous extract (DRAE) in BALB/c mice. <br> Methods: In the anti-breast cancer study, female BALB/c mice were divided into five groups (n = 12), which were (1) positive control (with breast cancer, untreated), (2) negative control (without breast cancer, untreated) and other three groups of mice with breast cancer treated with 1 000, 500 and 250 mg/kg of DRAE, respectively, by oral gavage for 28 days. All mice except from the negative control group were injected into the mammary fat pad with 4T1 cells (1 × 105 4T1 cells/0.1 mL of phosphate buffer solution). DRAE was administered orally on Day 11 after the tumor has developed. <br> Results: The tumor volume of the 1 000 mg/kg of DRAE group reduced significantly compared to the positive control while treatment with 500 mg/kg of DRAE had signif-icantly inhibited metastasis to the heart. In the acute toxicity study, treatment with up to 5 000 mg/kg of DRAE was not toxic to the animals, indicating its safety when a large amount of this plant extract was ingested. Based on the sub-acute toxicity study, treatment of the highest dose of DRAE (1 000 mg/kg) had mild liver toxicity indicated by mild focal hemorrhage. <br> Conclusions: DRAE possesses anti-breast cancer properties but at the same time it shows mild toxicity to the liver. The non observable adverse effect dose for DRAE is 500 mg/kg.