The use of plants for healing purposes predates recorded history and forms the origin of much of modern medicine. Many conventional drugs originate from plant sources: a century ago, most of the few effective drugs were plant-based. Examples include aspirin (from willow bark), dioxin (from foxglove), quinine (from cinchona bark), and morphine (from the opium poppy). The development of drugs from plants continues, with drug companies engaged in large-scale pharmacologic screening of herbs.
Herbs have a variety of uses including culinary, medicinal, and, in some cases, spiritual.