Reishi mushrooms include several species belonging to the genus Ganoderma. They are one of the oldest known types of medicinal mushrooms. Reishi mushrooms have also been the subject of more extensive research than any other type of medicinal fungus. Although, they did not rise to popularity in the Western world until the 20th century. Today, reishi mushrooms are a popular daily wellness supplement around the globe, as well as a component of treatment for a range of acute and chronic conditions.