Ganoderan (GAN), an immunomodulating ${eta}$-glucan from mushroom Ganoderma lucidum, was evaluated for its ability to induce formation of nitric oxide (NO), tumor necrosis factor-${alpha}$(TNF-${alpha}$) and transforming growth factor (TGF-${eta}$) from rat Kupffer cell in vitro. Hepatic macrophages activated by GAN significantly elevated concentration of NO and TNF-${alpha}$ in cultured medium, but not significantly elevated that of TGF-${eta}$. GAN-activated Kupffer cells secrete 14.9${mu}$M (p<0.01) of NO and 2619.5${ ho}$g/ml (p<0.01) of TNF-${alpha}$after 36hr of incubation at 37$^{circ}C$. The results revealed that GAN enhanced 4-fold production of NO and 19 fold formation of TNF-${alpha}$ compared to the control. The proliferation of GAN-activated Kupffer cells was inhibited as compared with its negative control. Comparing the activity among glucans derived from microorganisms, highly branched zymosan, glucomannan from Saccharomyces cerevisiae, significantly increased TNF-${alpha}$ and NO production. These results indicate that the ${eta}$-glucan from G. lucidum activates rat Kupffer cell and secretes NO and TNF-${alpha}$. It also suggest that rat Kupffer cell posses certain receptor for ${eta}$-anomeric glucan.