Here is some information I found online it is from Web MD. Hope it helps.
Kratom is a tree. The leaves are used as a recreational drug and as medicine. Kratom is banned by some states in the U.S. due to safety concerns.
People use kratom for withdrawal from heroin, morphine, and other opioid drugs, as well as cough, depression, anxiety, and many other conditions, but there is no good scientific evidence to support these uses.
Using kratom can also be unsafe. Kratom use has been linked to serious side effects including hallucinations, seizures, liver damage, withdrawal, and death. Due to these and other serious safety concerns, the U.S. Food and Drug Administration (FDA) continues to warn people to avoid using products containing kratom or its ingredients.
How does it work?
Kratom contains a chemical called mitragynine. Mitragynine works like opioid drugs such as codeine and morphine to relieve pain.