The FDA has listed the over-the-counter herbal drug kratom as a "drug of chemical concern."
The drug has been linked to 91 fatal overdoses in the U.S. from July 2016 to December 2017, according to the Centers for Disease Control.
However, kratom overdoses account for less than 1 percent of fatal overdoses.
The CDC analysis comes as kratom poisonings rose 50-fold from 13 in 2011 to 682 in 2017.
About 3 million to 5 million people use kratom, which, at small doses, acts as a mild stimulant but side effects include agitation, irritability, and fast heart beat (tachycardia). At moderate to high doses, it can produce opiod-like effects, including some pain relief. However, serious clinical effects include seizures, respiratory depression, slow heart beat (bradycardia), renal failure, and cardiac arrest.
The FDA has not shown the drug to be dangerously addictive. According to the American Kratom Association, the drug has not been shown to be a risk to public safety.
