Herbal medicine (also called herbalism, phytomedicine or phytotherapy) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. With worldwide research into pharmacology, some herbal medicines have been translated into modern remedies, such as the anti-malarial group of drugs called artemisinin isolated from Artemisia annua, a herb that was known in Chinese medicine to treat fever. There is limited scientific evidence for the safety and efficacy of many plants used in 21st century herbalism, which generally does not provide standards for purity or dosage. The scope of herbal medicine sometimes include fungal and bee products, as well as minerals, shells and certain animal parts.

Paraherbalism describes alternative and pseudoscientific practices of using unrefined plant or animal extracts as unproven medicines or health-promoting agents. Paraherbalism relies on the belief that preserving various substances from a given source with less processing is safer or more effective than manufactured products, a concept for which there is no evidence.