Oecophylla longinoda has some reported medicinal uses, including antimicrobial, analgesic, and anti-inflammatory activities. This study was designed to investigate the Oecophylla longinoda methanol extract to evaluate the toxicity profiles of its acute and sub-acute effects. The experiments were conducted to determine the oral median lethal dose (LD₅₀) and other gross toxicological manifestations on an acute basis. In the first phase of the acute toxicity study, three per group were administered Oecophylla longinoda at single oral doses of 10, 100, and 1000 mg/kg body weight, and 1600, 2900, and 5000 mg/kg of Oecophylla longinoda in the second phase. In the sub-acute studies, the mice were orally administered 2.5 g/kg Oecophylla longinoda per day for 14 consecutive days. Rat body weight and fluid intake were recorded during the 14 days. The rat kidney, heart, liver, and blood sera were obtained for weight, histological, and biochemical markers including glucose, cholesterol, proteins, triglycerides, enzymes including ALT, AST, and ALP, as well as electrolytes (sodium and potassium) examinations. Results show that the methanol extract of Oecophylla longinoda is safe, and no significant changes in the biochemical markers that indicate harmful effects on the kidney and liver were observed in mice. However, the liver showed slight changes while the kidneys and heart remained healthy in mice exposed to Oecophylla longinoda. The no-observed-adverse-effect limit was 5000 mg/Kg body weight/day.