Mitragyna speciosa (ketum, kratom or kratum) is a tropical deciduous and evergreen tree in the coffee family (Rubiaceae) with a long history of medicinal use in Southeast Asia, particularly in Thailand or Malaysia.  In low dosages of a few grams of leaf, kratom functions primarily as a stimulant, with effects similar to caffeine without the marked jitteriness of drinking several cups of coffee. In higher dosages, kratom functions as a neurological opiate, triggering the mu opiate receptors in the brain, even though kratom is chemically different from the opium derived medications such as codeine, morphine, hydrocodone, and oxycodone.