Salvia divinorum (known colloquially by its genus name Salvia) is a psychoactive herb which can induce dissociative effects. It is a herbaceous perennial in the Lamiaceae (mint) family. The specific name, Salvia divinorum, was given because of its traditional use in divination and healing—it literally translates to "diviner's sage" or "seer's sage".

Salvia divinorum has a long and continuing tradition of religious use as an entheogen by indigenous Mazatec shamans, who use it to facilitate visionary states of consciousness during spiritual healing sessions. Its native habitat is within the isolated Sierra Mazateca cloud forest in Oaxaca, Mexico, growing within shaded and moist areas. It grows to well over a meter in height. It has hollow square stems, large green leaves, and occasional white flowers with purple bracts. Botanists have not determined whether it is a cultigen or a hybrid.

Its primary psychoactive constituent is a structurally unique diterpenoid known as salvinorin A, which is a potent κ-opioid receptor agonist. Salvia divinorum can be chewed, smoked, or taken as a tincture to produce experiences ranging from laughter to much more intense and profoundly altered states. The duration of effects is much briefer than those of other psychoactive compounds, typically only minutes in length.

The most commonly reported after-effects include an improved mood and sensations of insight, calmness, and connection with nature—though rarely it may also cause dysphoria. Salvia divinorum is generally understood to be of low toxicity (high LD50) and low addictive potential; as a κ-opioid agonist, it may have potential as an analgesic and as a therapeutic tool for treating drug addictions.

Salvia divinorum is native to certain areas of the Sierra Mazateca in Oaxaca, Mexico, where it is still used by the Mazatec. While it is primarily taken to facilitate shamanic visions in the context of curing or divination, it is also used remedially at lower dosages. For example, it is prescribed as a diuretic and to treat ailments including diarrhea, anemia, headaches, rheumatism, and a semi-magical disease known as panzón de borrego, or a swollen belly (literally, "lamb belly").

The history of the plant is not well known, and there has been no definitive answer to the question of its origin. Speculation includes Salvia divinorum being a wild plant native to the area; a cultigen of the Mazatecs; or a cultigen introduced by another indigenous group. Botanists have also not been able to determine whether it is a hybrid or a cultigen.