OBJECTIVE: To investigate the effects of non-ionic polyacrylamide (model: NPAM 1400) alone or combined with nanoscale silica gel (nSiO2) on the stability of Glycyrrhetinic acid lipo-emulsion. METHODS: UV-spectrophotometer was used to determine absorbance of diluent at 500 nm before and after lipo-emulsion centrifugation. Using the preparation without stable excipient as blank, stability coefficient (KE) and it ratio (KE/KE blank) were calculated. Effects of different concentrations (200-600 mg/L) of non-ionic polyacrylamide on the stability of Glycyrrhetinic acid lipo-emulsion were evaluated. The optimal concentration of non-ionic polyacrylamide alone was determined primarily, and then the effects of it combined with different concentrations of hydrophilic nSiO2 (0.2%, 0.3%, 0.4%) or hydrophobic (0.2%, 0.3%, 0.5%) on the stability of Glycyrrhetinic acid lipo-emulsion were investigated. RESULTS: When adding non-ionic polyacrylamide alone, KE of Glycyrrhetinic acid lipo-emulsion mixed with 300 mg/L non-ionic polyacrylamide was the lowest,KE/KE blank was 0.22; when combined, KE of Glycyrrhetinic acid lipo-emulsion mixed with 300 mg/L non-ionic polyacrylamide and 0.2% hydrophobic nSiO2 was the lowest, KE/KE blank was 0.27. CONCLUSIONS: Non-ionic polyacrylamide alone or combined with nSiO2 all can promote the stability of Glycyrrhetinic acid lipo-emulsion, among which 300 mg/L non-ionic polyacrylamide alone is the best.