Nowadays it is a well established fact that there is a strong relationship between health and Diet. In the last two decades Probiotics have become immensely popular resultant,enormous scientific evidences in favor of their beneficial effects on human health. The importance of probiotics is momentous because of its commercial and clinical use. Probiotics helps in improving gut micro–flora, thereby plays an important role in improving Host’s health. This magnificent relationship has attracted extensive research. Meticulously, Probiotics play a key role in defense mechanism. By modifying intestinal micro–flora, probiotics directly or indirectly manipulates the health of the Host by proving protection against harmful bacteria. Likewise Probiotics has influence on immune system, symptoms of Lactose Intolerance, stimulates toxin elimination and also have other beneficial effects that are related to gastrointestinal tract. In this work, health benefits provided to human being by probiotics are being reviewed and discussed.