A 90-day subchronic toxicity study of submerged mycelial culture of Cordyceps militaris in rats.

Cordyceps militaris (C. militaris) is a parasitic fungus that grows on the larvae of Lepidoptera. It is a well-known fungus with immunomodulatory activity. The study was conducted to clarify the edible safety of C. militaris mycelium for long term use. Eighty Sprague-Dawley (SD) rats were divided into four groups (10 males and 10 females in each group). Rats were orally administrated with reverse osmosis water or 2000, 3000 and 4000 mg per kg BW per day freeze dried C. militaris mycelium powder for 90 consecutive days. Clinical observation was carried out daily. The body weight and feed intake of the rats were recorded weekly. At the end of the study, all rats were sacrificed and the blood and organs were collected for hematology, clinical biochemistry and histopathological examination. All animals survived until the end of the study. During the study period, no abnormality occurred in clinical signs, body weight, feed intake, ophthalmological examination and urinalysis. There were no significant differences upon gross necropsy between the treatment and control group. Hematology, clinical biochemistry parameters and histopathological examination showed no treatment-related change. According to the results, the no-observed-adverse-effect level of C. militaris mycelium is 4000 mg per kg BW per day for male and female SD rats.