Known as the king of mushrooms, reishi mushrooms contain polysaccharides that demonstrate prebiotic effects and may increase counts of beneficial bacteria. Polysaccharopeptide (PSP) has been used widely as an adjuvant to chemotherapy with anti-tumor and broad immunomodulating effects. Reishi also contains the compound triterpene, which is known for its calming properties. These mood-boosting compounds may alleviate anxiety, depression and support better sleep. Reishi is considered to be beneficial for conditions such as rheumatoid arthritis, ulcerative colitis and fibro myalgia.