Taste, or gustation, is the chemical sense that detects substances dissolved in saliva. The basic qualities are sweet, sour, salty, bitter, and umami; additional qualities continue to be investigated.

Taste receptor cells are clustered in taste buds on the tongue and elsewhere in the oral cavity. Different receptor mechanisms detect different qualities: ion channels for salt and sour, G-protein-coupled receptors for sweet, bitter, and umami. Signals travel via cranial nerves to the brainstem, thalamus, and gustatory cortex. Taste collaborates closely with smell to produce the experience of flavor; when smell is blocked, much of flavor disappears.

Sensitivity to bitter compounds varies genetically and may have evolved to detect toxins. Preference for sweet and salty tastes is present early in life; acceptance of bitter and sour often requires learning. Taste disorders can result from medication, infection, or neurological damage and significantly reduce quality of life.

The tongue’s detection of dissolved chemicals is only the beginning of the richer experience of flavor.