Saliva is produced and secreted by salivary glands. The basic secretary units of salivary glands are clusters of acini cells. It is fluid that contains water, electrolytes, mucus, and enzymes, all of which flow out of the acinus into collecting ducts, certainly one of the most important components and an integral component to oral health. The protective role and benefits including buffering, remineralization in the healthy oral mucosa, immune defense, digestion, lubrication, diagnostic purpose, and proteome analysis are fulfilled by saliva. It aids in maintaining mucosal integrity and indigestion through salivary enzymes. The functions of saliva in maintaining oral health and the main factors that cause alterations in salivary secretion and the importance of saliva in caries development and bacterial plaque formation are discussed, and also its role and functions and organic and inorganic constituents in saliva are discussed. This is of great importance in ruminants, which have non-secretory forestomachs. Diseases of the salivary glands and ducts are not uncommon in animals and man, and excessive salivation is a symptom of almost any lesions in the oral cavity.