In the course of this experiment on the anti‐inflammatory effect of ginsenosides, protopanaxdiol ginsenosides have shown inhibition activities in inflammatory responses: NF‐κB, COX‐2, and iNOS were induced by TNF‐α. The responses of this experiment were evaluated by NF‐κB‐luciferase assay and RT‐PCR experiment of COX‐2 and iNOS genes. The NF‐κB expressions were inhibited by ginsenosides Rd, Rg5, Rz1, and Rk1 in a dose‐dependent manner. The IC50 values were 3.47, 0.61, 0.63, and 0.75 μM, respectively. Particularly, ginsenosides Rg5, Rz1, and Rk1 as converted ginsenosides from primary protopanaxdiol ginsenosidess significantly inhibited COX‐2 and iNOS gene expression. These inhibition levels were similar to sulfasalazine as reference material. Copyright © 2014 John Wiley & Sons, Ltd.