SKI306X is a herbal extract prepared from three herbs Clematis mandshurica, Trichosanthes kirilowii and Prunella vulgaris. It showed strong antiinflammatory actions on carrageenan-induced edema, acetic acid-induced pain, adjuvant-induced arthritis, and oxygen radical-generated reactions. In this study, the acute toxicity of SKI306X was evaluated in rats by a single oral administration. Thirty male and thirty female rats were divided into 6 groups according to the dose levels, respectively. After oral administration of SKI306X with several doses (5.0 g/kg, 3.3 g/kg, 2.2 g/kg, 1.5 g/kg, 1.0 g/kg), mortality, clinical signs, body weight, and gross findings in organs were examined. No toxic effect was shown in terms of mortality, clinical signs, body weight changes and gross findings. It is suggested the LD$_{50}$ of SKI306X would be more than 5.0 g/kg in rats.s.