Abstract: Small molecules isolated from Phytolacca americana L. grown in Guizhou province were evaluated for their anti tobacco mosaic virus (TMV) properties. Two triterpenoidsaponin compounds, eseulentoside D and esculentoside H showed higher activities than ningnanmycin AS. Their structures were determined by 1H NMR and IR analysis. Notably, it is the first time that triterpenoidsaponin compounds from P.americana was found with anti-TMV activity. This research provides useful information for the systemically study of P.americana. It is also high valuable for developing efficient, low toxicity, environmental friendly antiviral agents.