Cordyceps sinensis has been described as a medicine in old Chinese medical books and Tibetan medicine. It is a rare combination of a caterpillar and a fungus and found at altitudes above 4500m in Sikkim. Traditional healers and local people of North Sikkim recommend the mushroom, i.e., Yarsa gumba, Keera jhar (C. sinensis) for all diseases either as a single drug or combined with other herbs. The present study was undertaken to collect information regarding the traditional uses of cordyceps in Sikkim. It was found that most local folk healers/traditional healers use cordyceps for the treatment of 21 ailments. A modern literature search was carried out to assess whether the curative effects are valid or just blind faith of local people. Chemical constituents of cordyceps are given and pharmacological and biological studies reviewed. More mechanism-based and disease-oriented clinical studies are recommended.