A preliminary study on the carcinogenicity of the common fern Onychium contiguum

Onychium contiguum (Family Cryptogrammaceae) is a common terrestrial fern i n the Himalayas and in many other parts of the world. It is also present on the pastures in areas where grazing animals suffer from bovine urinary bla dder cancer. This fern is occasionally grazed by animals and in some areas it is present as a contaminant in grasses stored for winter feeding. Certai n species of the genus Onychium are used in folk medicine. Long-term exposu re of experimental animals to O. contiguum appeared to cause tumours of the ileum, urinary bladder and mammary glands.