Objective:To determine the anti-breast cancer activities and the safety oral consumption of Dillenia suffruticosa root aqueous extract(DRAE)in BALB/c mice.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(1×1054T1 cells/0.1 m L of phosphate buffer solution).DRAE was administered orally on Day 11 after the tumor has developed.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 significantly inhibited metastasis to the heart.In the acute toxicity study,treatment with up to5 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.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 is500 mg/kg. Objective: To determine the anti-breast cancer activities and the safety oral consumption of Dillenia suffruticosa root aqueous extract (DRAE) in BALB / c mice. 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 the 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 × 1054T1 cells / 0.1 mL of phosphate buffer solution). DRAE was administered orally on Day 11 after the tumor has developed. 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 significantly more metastasis to the heart. acute toxicity study, treatment with up to 5 000 mg / kg of DRAE was no t 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 (1000 mg / kg) had mild liver toxicity indicated by mild focal hemorrhage.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.