Eugenia jambolana Lam. (Myrtaceae) is widely used in folk medicine as an antidiabetic, but there is a lack of information about its toxicity, especially for the stem bark. The present study evaluated acute oral and repeated-dose toxicity of the stem bark aqueous extract of Eugenia jambolana (EJ) in albino mice and Wistar rats. In the acute toxicity tests, mice received oral doses of EJ extract as 300, 2000, and 5000 mg/kg body weight. Mortality, signs of toxicity, body weight, food consumption, and gross findings were observed for 14 days post-treatment. In repeated toxicity, rats were orally treated with 300, 1000, and 2000 mg/kg body weight, and animals were observed till the 28th day of treatment. At the end of the study period, surviving animals were fasted overnight and anesthetized for blood collection and removal of some vital organs for histopathology. No significant differences were noted in body and organ weights between the control and treated groups from either of the studies. In addition, hematological parameters, e.g., red blood cell count (RBC), hemoglobin concentration (Hb), mean corpuscular hemoglobin concentration (MCHC), platelets (PLT), and white blood cell differential count, biochemical parameters, e.g., blood glucose, creatinine, blood urea nitrogen (BUN), alkaline phosphatase (ALP), bilirubin, total protein, and albumin, and ions, e.g., potassium, sodium, chloride, calcium, and phosphorus, were studied in the repeated-dose toxicity study. In conclusion, these investigations indicate the safety of acute and repeated oral administration of the aqueous extract of EJ stem bark, suggesting therefore that it may be continuously used safely.