Subacute toxicity study was carried out by administering orally daily doses of 0, 0.5 and 2.0 g/kg of crude extract of Anoectochilus formosanus Hayata (AFE) to groups of male and female rats for 90 days. At the dose of 2.0 g/kg, retardation of weight gain and slight increase in urinary ketones were noted in the males while decreased numbers of segmented neutrophils, decrease in serum lactate dehydrogenase activity, slight decrease in serum calcium and phosphorus levels, and increase in tissue weights of the pituitary, liver and kidney were observed in the females. However, no accompanying histopathological changes were observed. In conclusion the dose with which no toxicological manifestations were associated was likely 0.5 g/kg or below.