Oregon has a diverse range of native plants. The mild climate and ample rainfall has allowed many different species to naturalize and compete with native plants. Over millions of years plants have adapted numerous ways to avoid predation and to compete for growing space and nutrients. One way is for a plant to produce a toxin that deters insects and animals from feeding on the plant. Fortunately, some of these chemicals in low dosages can also have positive medicinal uses.
Foxglove (scientific name Digitalis purpurea) was originally native to Europe but has become naturalized in Oregon and the Pacific Northwest region. It is a herbaceous biannual plant. It only produces leaves and stems the first season, then flowers and seeds in the second season before it dies off. Foxglove grows up to 6 feet tall and has a conical shaped flower spike at the top of the plant with numerous purple tube shaped flowers. It prefers very rich soil near woodlands but can adapt to a variety of conditions as long as it stays moist. It is also a popular garden plant and only poisonous if eaten. This plant is the source of the drug digitalis which is used to treat some heart conditions.
Stinging nettles (scientific name Urtica dioica) is a notorious plant for hikers and naturalists in Oregon. It is a native perennial plant that reproduces by seed and by underground rhizomes. It is often found in drainage ditches and in disturbed areas. It can also be found in wooded areas. It forms large colonies of plants that grow up to 9 feet tall. The long slender herbaceous stems are covered with fine hairs. When you touch the plant they become embedded in your skin and release an irritating formic acid that lasts from one to 24 hours. Other than skin irritation it is relatively harmless. The juices from the crushed leaves of curled dock (Rumex creispus), another Oregon plant, helps sooth the burning.
Poison oak (scientific name Rhus diversiloba) is native to the western side of the Cascade Mountains in Oregon. It is a widely spread woody shrub or vine that is closely related to poison ivy and poison sumac. It grows in woody areas usually along fence lines and under trees. It can grow up a tree trunk like a vine and small rootlets will attach it to it's support. The leaves are in sets of threes and have a glossy red to green color.
All parts of the plant except for the pollen are poisonous and contain an oil called urushiol. When the oil comes in contact with the skin it causes minor to severe rashes and even death in a few cases. In more severe cases the oil causes blistering. Direct contact is not needed, the oil can be transferred to the skin by clothing or tools that came in contact with the plant. Inhaling the smoke of burning poison oak can cause damage to the lungs.