With the mention of kratom in this discussion, I'd like to post this important note from a Mayo Clinic pharmacist:

Kratom is a natural product but it does have significant risks and side effects. Because of these risks the FDA banned import of Kratom in August 2016 and issued a notice of intent to classify 2 chemicals in Kratom as Schedule 1 drugs (the same category as heroin). There are no FDA-approved uses for kratom, and the agency has received concerning reports about the safety of kratom. FDA is actively evaluating all available scientific information on this issue. (2019) https://www.fda.gov/news-events/public-health-focus/fda-and-kratom

Kratom can cause dependence and withdrawl symptoms including aggression, anxiety and other negative psychiatric effects, muscle aches, spasms, tremors, insomnia, fever and upset stomach. It can also cause dangerous slowed breathing and seizures. It can worsen psychiatric disease and may increase the risk of suicide. Kratom can impair liver function. Kratom interacts with other herbal medications including Jimson Weed. It interacts with sedating medications. It has the potential for many other drug interactions because of the way it is metabolized.

For more information see:
- National Institute of Health: Drug Facts, Kratom https://www.drugabuse.gov/publications/drugfacts/kratom
- Center for Disease Control https://www.webmd.com/mental-health/addiction/news/20190411/cdc-americans-are-dying-from-kratom-overdoses#1