Saliva is a complex fluid with multifunctional roles in the oral cavity. Even though its importance on oral health maintenance has long been recognized, the critical functions of saliva on food oral processing and perception have only been acknowledged recently.This review will present saliva as an unavoidable ingredient that has a profound impact on our eating experience. We aim to emphasize that what is perceived in-mouth is a food-saliva mixture rather than the food on the plate. The mechanisms through which saliva interacts with food components will be discussed in detail together with the implications of food-saliva interactions to food oral processing and perception.At the structural level, saliva facilitates the breakdown of food structures, contributes to the formation of a cohesive bolus and increases the degree of lubrication for a safe swallow. At the molecular level, saliva interacts with food components, leading to the formation of new compounds, complexes and microstructures. The mechanisms underlying food-saliva interactions include surface coating and clustering, colloidal interactions, complexation, enzymatic breakdown and binding of aroma compounds.