As of 2018, the efficacy and safety of kratom are unclear, and the drug was unapproved as a therapeutic agent due to the poor quality of the research. In 2019, the United States Food and Drug Administration (FDA) stated that there is no evidence that kratom is safe or effective for treating any condition. Some people take it for managing chronic pain, for treating opioid withdrawal symptoms, or for recreational purposes. The onset of effects typically begins within five to ten minutes and lasts for two to five hours
In cultures where the plant grows, kratom has been used in traditional medicine. The leaves are chewed to relieve musculoskeletal pain and increase energy, appetite, and sexual desire in ways similar to khat and coca. The leaves or extracts from them are used to heal wounds and as a local anesthetic. Extracts and leaves have been used to treat coughs, diarrhea, and intestinal infections. They are also used as intestinal deworming agents in Thailand.
Kratom is often used by workers in laborious or monotonous professions to stave off exhaustion as well as a mood enhancer and painkiller. In Thailand, kratom was "used as a snack to receive guests and was part of the ritual worship of ancestors and gods". The herb is bitter and is generally combined with a sweetener
In 1836, kratom was reported to have been used as an opium substitute in Malaysia. Kratom was also used as an opium substitute in Thailand in the nineteenth century.