Before pharmaceutical medicine became a mainstay of modern culture, people relied on plants to provide their medicine. Researchers over the years derived several modern medicines from plants. They continue to do so, often finding evidence to support long-used herbal remedies. People have even witnessed and documented the use of medicinal plants by animals to treat ailments.
Echinacea purpurea, commonly known as purple coneflower, grows naturally in prairies in the United States. The roots of echinacea treat the immune system. The plant also contains anti-inflammatory properties. Echinacea blooms during the summer and thrives with little maintenance. The flowers attract butterflies and hummingbirds.
Another native to the United States, wild ginger (Asarum canadense) grows in moist, shady areas. Wild ginger makes an attractive ground cover with its heart-shaped leaves and spreading habit. The flowers appear in early spring, tucked under the leaves. In herbal medicine, wild ginger often makes an addition to calming teas both for its flavor and for mild sedative properties.
Stinging nettle (Urtica dioica), which is probably best known for the painful irritation caused by the leaves, makes an excellent restorative tonic. The cooked leaves contain minerals and vitamins, such as iron and vitamin C. Other properties of the herb include use as a diuretic, hair treatment and laxative. The plant grows wild in many parts of the world.
Calendula officinalis, or pot marigold, adds healing properties to skin care treatments. The sunny flowers contain antibacterial, antiseptic and antifungal properties. Calendula is a hardy annual with numerous varieties. The plant grows readily from seed and it blooms in hues of yellow, orange and red.
Another annual used for medicinal purposes, Borage officinalis, contains gamma-linolenic acid, or GLA. GLA, an Omega-6 fatty acid, shows promise in treatments for several conditions, including rheumatoid arthritis, diabetic neuropathy, allergies, hypertension and breast cancer. Borage's tiny, purplish-blue flowers attract bees and other pollinators. The fresh leaves may cause irritation when handled.
Though not as well known for their medicinal properties, several trees have long histories of use as medicine. The bark of the willow tree (Salix alba) provided the property for the development of aspirin and salicin. The use of willow bark dates back to Hippocrates. The bark has anti-inflammatory properties and relieves pain.
The bark of the wild cherry tree (Prunus serotina) makes an effective cough remedy when processed into syrup. The wild cherry, an eastern United States native, produces small, edible cherries.
Ginkgo biloba, one of the oldest known species of tree, has use as herbal medicine. The dried, fan-shaped leaves of the Ginkgo tree improve circulation and memory. Because of these factors, researchers are testing its effects on Alzheimer's disease.