Herb: Brittle Bladder Fern

Latin name: Cystopteris fragilis

Synonyms: Felix fragilis, Polypodium fragile

Family: Dryopteridaceae (Wood Fern Family)

Medicinal use of Brittle Bladder Fern:

A decoction of the roots has been used as an anthelmintic enema. A cold compound infusion of the plant has been used both internally and externally as a treatment for injury.

Description of the plant:


15 cm
(6 inches)

Habitat of the herb:

Rocky woods, shady rocks and walls, especially on basic rocks, to 1200 metres.

Edible parts of Brittle Bladder Fern:

Root. An emergency food, it is only used when all else fails.

Other uses of the herb:

Plants can be grown as a ground cover when planted out about 15cm apart each way.

Propagation of Brittle Bladder Fern:

Spores - best sown as soon as ripe on the surface of a humus-rich sterilized soil. Keep the compost moist, preferably by putting a plastic bag over the pot. Germinates in 1 - 3 months at 20C.Pot on small clumps of plantlets as soon as they are large enough to handle and keep humid until they are well established. Do not plant outside until the ferns are at least 2 years old. Division in spring.

Cultivation of the herb:

Rocky woods, shady rocks and walls, especially on basic rocks, to 1200 metres.

Known hazards of Cystopteris fragilis:

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable. Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase.

Plant information taken from the Plants For A Future.