Marginal fern

Tbe Male Fern along with the Marginal Fern Dryopteris margin-alis) have long been known to the pharmaceutical and medical professions as the source of the drug Aspidium, a most valuable remedy for the expulsion of tapeworm. The parts of these plants employed are the rhizome and stipes which are collected in autumn, freed of the roots and dead portions and dried at a temperature not exceeding 7o°C. 

Common/vernacular names European aspidium and male fern (D. filix-mas) American aspidium and marginal fern (D. marginalis). 

In people whose thiamin intake is marginal, colonization of the gastrointestinal tract with thiaminolytic microorganisms may be a factor in the development of beriberi. The thiaminases present in raw fish can result in so-called Chastek paralysis of foxes and mink, as a result of destruction of thiamin, and may be important in parts of the world where much of the apparent thiamin intake is from fish that is eaten raw or fermented. The polyphenols and thiami-nase in bracken fern can cause thiamin deficiency (blind staggers) in horses, and tannic acid in tea and betel nut have been associated with human thiamin deficiency. 

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