The rhizome of Dryopteris Filix-mas and of Dryopteris marginalis, Asa Gray (Nat. Ord. Filices). World-wide ferns of the Northern Hemispheres. Dose, 1 to 4 drachms.
Common Names: (1) Male Fern; (2) Marginal Shield Fern.

Principal Constituents.—Oils, resins, filicin, and filicic acid, the poisonous principle.
Preparation.—Oleoresina Aspidii, Oleoresin of Aspidium (Oleoresin of Male Fern). Dose, 30 grains but once a day. Do not give with oils.

Action and Toxicology.—When freely absorbed the oleoresin causes nausea, vomiting, purging, severe abdominal pain, headache, dizziness, muscular prostration, tremors, cramps, dyspnea, cold perspiration, cyanosis, collapse, and death. In some cases amblyopia results, and permanent visual and aural disturbances have resulted from its toxic action. Unless the doses are excessive or frequently given, or given with oil, as castor oil, such accidents are less likely to occur. The treatment consists in stimulation by ammonia and purging by Epsom salt.

Therapy.—A most certain taenicide, effectually removing tapeworm, especially the Bothriocephalus latus and the Taenia solium, and said to be less effective upon the Taenia medio-canellata. Prepare the patient in the usual manner over night for the administration of taenicides by purging and fasting. In the morning administer 30 grains of the oleoresin in capsules or flavored emulsion, follow at midday with a full meal without fats, and in the evening give a brisk saline cathartic. Under no circumstances must oils, especially castor oil, be given with it during the treatment. They favor absorption of the filicic acid, thought to be the toxic principle. Aspidium is seldom used; the oleoresin being preferred. The latter is also effectual against the hook-worm (Uncinaria americana).

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.