Kratom behaves simmilar to morphine and has been used in the management of chronic pain and recreationally. Kratom has also been used as a way to treat opiate dependence.
Today in southeast Asia, Kratom consumers are not frowned upon, or is it even considered a drug. There is no discrimination from eaters of the plant that has been part of the culture for thousands of years.
Mitragyna speciosa (Kratom) is a tropical tree native to southeast asia. It's leaves have been used by many for medicinal properties. It's leaves are chewed to gain an uplifting feeling and have been used for medical purposes for many years.
Here in the States, the FDA has not evaluated Kratom for human consuption. It's Illegal still in Thailand too.
In 1948 opium popularity, taxed by the government, made it really expensive and Kratom was not,... so the alternative put a dent in government tax revenue. So making Kratom Illegal made the most since.