Mannose is a monosaccharide widely distributed in body fluids and tissues, especially in the nerve, skin, testicles, retina, liver and intestines. It is used to synthesize glycoproteins and participate in immune regulation. In recent years, mannose has been applied more and more widely in the biomedical context as people have a deeper understanding of its biological effects. This review introduces the use of mannose in treating various diseases (including cancer, urinary tract infections, type 1 diabetes, and diabetic wounds), preventing pancreatic fistula, and improving magnetic resonance imaging for acute pancreatitis. We also demonstrate that mannose has the potential for clinical applications.