Língzhī (traditional Chinese: 灵芝; Japanese: reishi, 靈芝; Korean: yeongji, 영지) is the name for one form of the mushroom Ganoderma lucidum, and its close relative Ganoderma tsugae. Ganoderma lucidum enjoys special veneration in Asia, where it has been used as a medicinal mushroom in traditional Chinese medicine for more than 4,000 years, making it one of the oldest mushrooms known to have been used in medicine.
The word lingzhi, in Chinese, means "herb of spiritual potency" and has also been described as "mushroom of immortality". Because of its presumed health benefits and apparent absence of side-effects, it has attained a reputation in the East as the ultimate herbal substance. Lingzhi is listed in the American Herbal Pharmacopoeia and Therapeutic Compendium.