Abstract: Eurycoma longifolia (EL) is a widely used herbal extract by men as aphrodisiac. However, there are no complete toxicity studies done on it. This study was conducted to determine the acute and subacute toxicities of EL on male Sprague-Dawley rats. Both acute and subacute studies were done according to the Organization for Economic Cooperation and Development (OECD) Guideline. In acute toxicity study, Eurycoma longifolia (EL) aqueous extract at the dose of 5000 mg kg-1 body weight was given to rats within 24 h by oral gavage. In subacute toxicity study, the first group of rats served as the control group while the other three groups were given EL aqueous extract at doses of 600, 1200 and 2400 mg kg-1 bodyweight, respectively via daily oral gavages for 28 days. Histopathological examination was done on the testes, kidneys and liver for acute and subacute toxicity study. Biochemistry and haematology analysis as well as thin blood film were done for subacute toxicity study. The oral LD50 for EL aqueous extract was found to be more than 5000 mg kg-1. No pathological changes were observed in the rat liver, testes and kidneys in the acute toxicity study. Subacute toxicity study showed no significant changes in biochemical and haematological parameters while thin blood films were normal. No pathological changes were found in the testes and kidneys. However, hydropic changes were found in the livers of a few of the treated rats. This study shows the EL extract does not cause acute toxicity but was found to cause hepatotoxicity in subacute toxicity study.