Aspidium oleoresin, bear’s paw, bontanifuge, Dryopteris filixmas, Extractum filicis, E. filicis aethereum, E. filicis maris tenue, knotty brake, male shield fern, marginal fern, sweet brake, wurmfarn
Male fern is a plant found in temperate zones of Europe, northern Asia, and North and South America. The medicinal parts are the dried fronds, the dried rhizome collected in autum with the leaf bases, the fresh rhizome, and the fresh aerial parts.
Filicinic and flavaspidic acids are the main active components responsible for herb’s anthelmintic properties. Other components include volatile oils, tannin, paraspidin, and desaspidin. Desaspidin and aspidin may have antitumor activity. Male fern is available as extract (1.5% to 22% filicin), draught (4 g of male fern extract), and capsules.
Reported uses
Male fern has long been used as an anthelmintic against pork tapeworm (Taenia solium), beef tapeworm (T. saginata), and fish tapeworm (Diphyllobothrium laturn). It’s also applied topically for muscle pain, arthritis, sciatica, neuralgia, earache, and toothache.
Safety Risk Male fern is toxic Ingestion isn’t recommended. In poisoning or overdose, optic neuritis, blindness, seizures, psychosis, paralysis, respiratory and cardiac failure, coma, and death may ensue. The patient should seek emergency medical care.
Administration
- Extract: Initial dosage 6 to 8 g for adults and 4 to 6 g for children over age 4 years. In the case of an unsuccessful cure, the treatment may be repeated, but only after an interim of a few weeks. The single and daily maximum dosage of liquid extract is 3g
- Oil solution: The maximum daily dosage is 20 g
- Draught: Dosage is 50 ml given by duodenal tube; treatment may be repeated in 7 to 10 days, as needed
- Homeopathic formula: Dosage is 5 drops, 1 tablet, or 10 globules every 30 to 60 minutes (acute) or 1 to 3 times daily (chronic)
- Parenteral: Dosage is 1 to 2 ml subcutaneously, three times a day in acute cases, daily in chronic cases.
Hazards
Therapeutic doses of male fern may cause headache, seizures, queasiness, psychosis, paralysis, and coma. Other possible complications include heart failure, optic neuritis, permanent visual disorders, severe abdominal cramps, diarrhea, nausea, and vomiting. The patient may also experience hepatotoxicity, hyperbilirubinemia, jaundice, dyspnea, respiratory failure, and albuminuria.
Antacids, H2 blockers (such as famotidine and ranitidine), proton pump inhibitors (including lansoprazole and omeprazole), and other alkalinizing drugs inactive the acid components of male fern. A diet high in fats and oils may cause an increased absorption of male fern and potentiate the risk of toxicity.
Pregnant women should avoid using this herb because it may stimulate uterine muscle. Patients who are breast-feeding, infants, children younger than age 4 years, geriatric patients, and debilitated patients should also avoid use. Patients who are hypersensitive to male fern or its components, and those with anemia, GI ulceration, cardiovascular disease, diabetes, and hepatic or renal failure, should avoid use.
Clinical considerations
- Male fern has a narrow window of intended activity; toxic effects can occur in that window.
- The draught is considered a more effective anthelmintic than capsule form.
- Patients being treated with drugs that affect bilirubin conjugation or alter liver enzyme levels should use herb with caution or avoid it.
- Patient may take a laxative the evening before herb treatment and a second laxative dose with the herb the next morning before eating.
- Monitor patient’s liver function tests and renal function.
- Monitor fluid intake and electrolyte loss in patients who develop vomiting and diarrhea.
- Inform patient that toxic effects can occur with normal doses.
- If patient takes an antacid, H2 blocker, or proton pump inhibitor, tell him to avoid using this herb.
- Tell patient to avoid fats and oils while taking herb.
- Advise patient that conventional anthelmintics for tapeworms are safer than male fern.
- Urge patient to seek medical care for suspected tapeworm before using this herb.
- If patient has persistent abdominal pain or yellowing of the skin and eyes,
- stress that he should obtain medical care.
- If patient is pregnant or breast-feeding or has anemia, a GI condition, or cardiac, hepatic, or renal impairment, caution against using herb.
- Tell patient to remind prescriber and pharmacist of any herbal or dietary supplement that he’s taking whenobtaining a new prescription.
- Advise patient to consult his health care provider before using an herbal preparation because a treatment with proven efficacy may be available.
Research summary
Male fern is considered toxic at therapeutic doses and shouldn’t be used.