Although not representing plants from all over Indonesia, the degree of acute toxicity of the infusion of some medicinal plants were determined, and clinical signs recorded. Using the clasification of Cleason cs the LD50 of Messua ferrae Linn needs special attention due to being near the maximal border line. The rest can be classified as practically non toxic. Based on the clinical signs Piper betle Linn needs some attention. At dosage half the LD50, it is diuretic and near the LD50 diarrhoea is seen besides diuresis.