Kratom (Mitrogyna Speciosa) is a South East Asian tree contains psychotropic alkaloids mitragynine and 7-Hydroxymitrogynine in its leaves. In its home region, it has a long history of use by farmers and other manual workers, who claim it boosts productivity. The leaves of this plant (typically made as a tea) have gained popularity internationally in recent years, particularly in the United States. Its legality varies between areas and countries, despite the fact that it is not under international supervision (as is commonly the case with ethnobotanical psychoactives). Little is known about the level of use in Europe, particularly in countries where it is prohibited, such as the United Kingdom, where it has been regulated since 2016 under the Psychoactive Substances Act.

Over 40 distinct alkaloids, as well as a variety of other chemicals, are found in kratom. Mitragynine and 7-hydroxymitragynine are two alkaloids that function as partial agonists on opioid receptors, which means they have effects that are similar to opioid-based drugs but are less potent. This is mainly due to the low concentrations of psychoactive chemicals in the plant matter (typically 1–1.5 percent), which means that a significant amount of kratom must be eaten before a psychoactive effect is visible. At slightly lower doses, bodily effects may be visible; some users say that the main (or only) effect is a lack of exhaustion or pain. Mitragynine has a wide affinity for many different receptors in the body, which could explain its complicated effect on energy and mood