The Chinese herbal drug DongChongXiaCao, a medicinal and edible mushroom originating from the fungus Cordyceps sp., has been developed into health foods. Counterfeit and mimic types are frequently found in markets. Mycelial preparations of Cordyceps sinensis, via submerged fermentation, have been commercialized and also named DongChongXiaCao. This investigation endeavours to characterize the proximate composition, amino acid profiles, and contents of the bioactive ingredients, including adenosine and cordycepin. The total levels of amino acids were significantly different, ranging from 4 to 17%. Glutamic acid and aspartic acid were the two main amino acids in all samples tested; however, there was a third major amino acid. The level of total amino acids in the mycelium was only half that in the natural DongChongXiaCao. The bioactive ingredients adenosine and cordycepin did not exist in the counterfeit and mimic types. Adenosine was abundant in the fruiting body, amounting to considerably more than in the corpus of the natural DongChongXiaCao and the mycelium of C. sinensis. Trace levels of cordycepin were found in all the Cordyceps preparations. These findings suggest that adenosine and cordycepin might be used as indexing ingredients for differentiating Cordyceps from the counterfeit and the mimic.