To examine safety of Ganoderma lucidum, it was extracted with hot water (Fraction A). After the extract was dialyzed and freeze-dried, polysaccharide fraction (Fraction B) was obtained and examined for acute and subacute toxicity. In the acute toxicity tests of Fr. A and Fr. B on mice, both agents did not show any serious and lethal effects. The results showed that median lethal doses were higher than 5,000㎎/㎏. The experiments of oral administration of Fr. A (5,000㎎/㎏) to mice for 30 days showed that there were no changes in body weight, hematological tests and organ weight.