In terms of global health, diabetes mellitus (DM) is a significant issue. Complications, malfunctioning beta cells, and elevated blood glucose levels are the hallmarks of DM, the most common chronic illness. The oral hypoglycaemic drugs that are currently on the market have a risk of liver dysfunction, weight gain, and gastrointestinal discomfort. Using herbal plants with anti-diabetic qualities is quite prevalent throughout the world. The aim of the review study is to find out the effect of Psidium guajava on diabetics. In tropical and subtropical nations, Psidium guajava is a significant food crop and medicinal plant that is widely used as food and in folk medicine all over the world. It is a member of the Myrtaceae family, which has about 133 genera and 3800 species worldwide. Several metabolites in good yield and some of them have been found to have beneficial biological properties; these metabolites primarily belong to the phenolic, flavonoid, carotenoid, terpenoid, and triterpene families. This plant's extracts and metabolites, especially those from the leaves and fruits, have beneficial pharmacological properties. Anti-diabetic is one of the major pharmacological activity that shows by the plant. The plant's principal components have undergone comprehensive pharmacological testing, and the results indicate that they have anti-inflammatory, hypotensive, antifungal, antipyretic, and antioxidant effects.