Acute toxic hepatitis in male Wistar rats was produced by single injection of 40% CCl(4) (0.2 ml per 100 g body weight in oil). Pretreatment with various immunostimulators (bacterial polysaccharides prodigiozan and salmozan; yeast polysaccharides zymosan, peptidoglycan, and mannan; and hydrolytic enzyme egg lysozyme) produced a hepatoprotective effect correlating which the stimulatory influence on macrophages and increasing in the following order: mannan