Abstract: Objective To investigate the acute toxicity of Dendrobium devonianum extract in mice, and to evaluate the safety level. Methods There was no death in all mice after intragastrical administration of Dendrobium devonianum extract of the maximum concentration and maximum volume, and LD50 could not be detected, so the maximum tolerance dose was determined. Sixty mice were randomly divided into six groups (10 mice/group) by their sex and body weight, such as normal saline group, S1(2.8056 g·mL-1),S2(2.38476 g·mL-1),S3(2.0270 g·mL-1),S4(1.7230 g·mL-1),S5(1.4645 g·mL-1). After each mouse was given 0.5 mL materials by lavage within 1 day, the toxic reactions and body weight of mice were recorded daily for 7 days. The mice were sacrificed 7 days later, then the visceral changes were observed by naked eyes, and recorded liver, kidney weight. Results After the mice were given Dendrobium devonianum extract, there were no abnormal reactions and death or no significant changes of weight and liver, kidney index in mice during 7-day experimental period. And the maximum tolerance dose of Dendrobium devonianum extract in mice was 52.5590 g·kg-1. Conclusion Dendrobium devonianum extract has low toxicity, which is safe and reliable to eat.

Key words: Dendrobium devonianum, acute toxicity, maximum tolerance dose