This chapter provides an introduction to the sensory systems which determine human perception of foods. Since the same sensory systems are stimulated when a patient receives medication via the oral route, properties and effects described in the context of food perception are relevant to the understanding of the perception of pharmacological substances, and these should be taken into account when designing and/or formulating medicines. The different senses humans are endowed with serve different purposes. Properties of the senses of taste, smell, trigeminality, and touch (mouthfeel) are described as well as the integration of these into fl avor perception. It is discussed how memories carried by these senses, which are important for food choice behavior, are distinguished from memory in a “higher” sense such as vision. Orosensory perception is closely connected to different satiety mechanisms and reward in connection with foods and some aspects of these problems are described. Preference development and acceptance are particularly important in food perception and the mechanisms of these are explained. The same mechanisms are responsible for generation of aversions. Great care should be exercised to avoid these aversions in connection with administration of drugs.