Reishi

Reishi (Ganoderma lucidum in the broad sense — actually a complex of related species) is among the most culturally and medicinally significant fungi in the world. The species is a polypore — a hard, woody, perennial bracket fungus — that grows on dying or dead hardwoods, particularly oaks. Mature fruiting bodies have a glossy varnished red-brown surface that gives the species its scientific name (lucidum = "shining").

Reishi has been used in traditional Chinese medicine for over 2,000 years, with documentation in the foundational Shennong Ben Cao Jing herbal text from approximately 200 BCE. The species was traditionally called lingzhi ("herb of spiritual potency") and depicted in art, jade carvings, and religious imagery as a symbol of longevity, health, and good fortune. Wild reishi was historically extremely rare and was reserved for emperors, royal families, and the wealthy elite.

Modern reishi research has identified numerous bioactive compounds including triterpenoids (especially ganoderic acids), polysaccharides, and peptidoglycans. Studies have suggested potential immunomodulating, anti-inflammatory, anti-tumor, and cardiovascular benefits, though clinical evidence remains mixed and many traditional claims are not well supported by rigorous studies. Reishi extracts are widely sold as dietary supplements, but quality control across products varies enormously.

The species is too tough and bitter to eat as a culinary mushroom. Traditional and modern preparations are typically as a slow-simmered medicinal tea, a powdered supplement, or an alcohol-extracted tincture that concentrates the active triterpenes (which are not water-soluble) and polysaccharides.

Reishi cultivation became commercially significant in China starting in the 1970s and has spread globally. The species is one of the more straightforward medicinal mushrooms to cultivate on supplemented hardwood sawdust, with mature fruiting bodies harvestable within 4-6 months. Most commercial reishi today is cultivated rather than wild-harvested.