It has been known that Gentianae macrophyllae Radix is reputed to be effective in removal of 'Pungseub' and 'Heoyeol', and to be analgesic. Since ancient times, however, there have been many examples of substituting Lycoctoni Radix for Gentianae macrophyllae Radix. For that reason, this experiment was conducted to compare the diuretic, analgesic, anti-inflammatory, anti-pyretic, anti-bacterial effect, and toxicity of Lycoctoni Radix with those of Gentianae macrophyllae Radix. The results obtained in this work were summarized as follows; In the test of acute toxicity, Lycoctoni Radix was found to be toxic in comparison to Gentianae macrophyllae Radix which was found to be non-toxic. Both herbs were found to be diuretic and Gentianae macrophyllae Radix was more effective than the other and to be ineffective for the blood pressure and respiration. Lycoctoni Radix was found to be more analgesic than the other. Gentianae macrophyllae Radix was found to be more anti-inflammatory of the two and both demonstrated anti-pyretic effect. Anti-bacterial effect was detected only in Lycoctoni Radix. It is concluded that Gentianae macrophyllae Radix has mild diuretic, analgesic, anti-inflammatory and anti-pyretic effect, but Lycoctoni Radix, due to its toxicity, can not be substituted for Gentianae macrophyllae Radix.