Studies were carried out to determine whether inhibition of gangliosides on lymphoproliferation was related to interleukin (IL)-1. The results showed that gangliosides, GM1 and GT1b were able to inhibit the proliferation of spleen lymphocytes from C57BL/6J mice in dose-dependent fashion, whereas asialo-GM1 was not inhibitory. However, gangliosides, GM1 and asialo-GM1 did not suppress the production of IL-1 in Salmonella typhosa lipopolysaccharide (LPS)-induced peritoneal adherent cells. Various types of LPS including S. enteritidis, S. minnesota and Escherichia coli 055:B5 were used to stimulate the production of IL-1 in adherent cell cultures. The IL-1 production was not affected by gangliosides, GD1a and GD1b. Although GT1b suppressed IL-1 production of human monocytes to 82% of control level it did not, however, affect the IL-1 production of murine adherent cells. Thus, the inhibitory mechanism of gangliosides on murine immune cells remains unclear, and warrants further study.