Effects of swainsonine (SW: 8${alpha}$, ${eta}$-indolizidine-1alpha, 2${alpha}$, 8${eta}$-triol from Locoweed) on the cellular and nonspecific immune responses of lipopolysaccharide (LPS) wer e studied in ICR mice. Mice were divided into 4 groups (10mice/group), and LPS was given to each mouse 1 hr after i.p. injection with 3.7mg/kg of SW by i.p. injection twice a week for 14 days at a dose of 2mg/kg. Immune responses of the delayed-type hypersensitivity response (DTH) to sheep red blood cells (s-RBC), phagocytic activity and natural killer (NK) cell activity were evaluated. LPS treatment didn`t affect NK cell activity, phagocytic activity, DTH to s-RBC compared with those in controls, and phagocytic activity of sareoma 180 tumor bearing mice. However, circulating leukocytes were significantly decreased. Combinaton of LPS and SW increased circulating leukocytes significantly compared vath that in LPS alone, and DTH to s-RBC, NK cell activity and phagocytic activities of normal and sarcoma tumor bearing mice were not affected. These findings indicate that SW didn`t affected the cellular immune responses suppressed by LPS but significantly increased circulating leukocytes.