Pyrrosia lingua is a crested fern found in the mountainous areas of Jeju Island. It has a unique shape with wide leaves similar to the tongue, which gave its name Tongue fern in English. Its Korean name 'Seok Wi' means leathery leaf growing on rocks. It spreads as spores of a fern, and the brown sori are attached to the entire rear of the leaves. In Korean Traditional Medicine, the leaves and roots have been used to strengthen bronchitis, manage pain and diuresis. In a scientific study, methanol extract of P. lingua exhibited free radical scavenging activities when tested with DPPH, superoxide anion, nitric oxide, and ABTC assays. Some phenolic compounds are identified from pressurized liquid extract via GC/MS method; protocatechuic acid, ρ-coumaric acid, caffeic acid, chlorogenic acid were identified.