Mitragyna speciosa (Kratom) is a plant indigenous to some parts of Asia. People have been using it in areas like Thailand and Malaysia for centuries. Its leaves are taken for their depressant and stimulant qualities.
Depending on the dose used, it provides stimulant or depressant effects. Historically, low doses have been compared to coca and high doses have been compared to opium.
Some deaths and serious adverse effects have been connected to kratom, but those incidents usually involve other drugs. By itself, kratom is relatively safe for healthy people, even at strong+ doses. Chronic use may come with liver issues and problems like dry mouth and constipation.
Withdrawal does exist with regular use. It includes symptoms like irritability, diarrhea, pain, low motivation, and sleep trouble.