Sodium aurothiomalate (monogold monosodium mono-hydrogen sulfidobutanedioate), an anti-rheumatoid gold agent, was injected s.c. every other day for three times or given in drinking water daily for two weeks to Balb/C mice that were inoculated with syngeneic Meth/A cells i.p. As the control, cisplatinum was injected s.c. Survival curve was then observed and significance was determined by Wilcoxon's method. Statistically significant effects on survivals was obtained by 30 mg/kg/day s.c. or 75 mg/kg/day p.o. of gold. A dose of less than 12.5 mg/kg/day s.c. adversely affected the survival. Cisplatinum was significantly effective at the dose of 12.5 mg/kg/day, but markedly toxic at the dose of 125 mg/kg and adversely effective at 6 mg/kg/day s.c. The range of dose effectiveness of cisplatinum on survival was narrower than that of gold. Gold was effective when given s.c. or p.o. No significant toxicity of gold was observed at doses up to 125 mg/kg/day.