As an antiobesity, combination extract of Detam-1 soybean and Jati Belanda leaves must be safe and free from toxic agent, so the test of acute toxicity effect is needed. The aim of this study is to determine LD50 value, behavior, organ weight (OW), and organ index (OI) on mice after administrating Extract Ethanol Detam-1 soybean (EEDS), Jati Belanda ethanol extract (EEJB) and their combination. The methods which is used is true experimental research with completely randomized design according to BPOM 2014. Twenty female Swiss Webster mice were divided into four treatment groups. Group 1 (negative control), 2 (EEDS 2.000 mg/kgBW), 3 (EEJB 2.000 mg/kgBW), and 4 (combination of EEDS and EEJB 1:2). Data were analyzed using independent t test, α = 0.05. The result is there were no mortality and toxicity in all groups, no significant difference of OW and OI of eight major organs within the groups statistically (p> 0.05), except lungs, liver and spleen in group 2. The conclusion is LD50 value of EEDS, EEJB and their combination were above 2.000 mg/kgBW, no toxic effect on the behavior of mice; OW and OI on mice after administrating EEDS, EEJB and their combination.