Trichosanthin decoction has certain inhibitory effect on hemolytic streptococcus, dicoccus pneumoniae and Bacillus diphtheria in vitro, but has weak effect on bacillus typhoid, Bacillus aeruginosa, bacillus dysentery, Bacillus proteus and Staphylococcus aureus, Radix trichosanthis. The inhibitory effects of trichosanthin on 7 kinds of viruses were determined by lesion inhibition.