A group of scientists who have studied kratom are warning the Trump administration that banning the drug would worsen the opioid epidemic, following a declaration from the Food and Drug Administration that kratom has “opioid properties” and is associated with 44 deaths.

The drug, a Southeast Asian tree leaf, is legal under federal law, but FDA officials have recommended it be categorized as a Schedule 1 drug, which would effectively mean that scientists would be unable to study its effects. People who take the drug, which can be sipped in a tea or taken as a pill, say that is has helped them beat off cravings for opioids and has alleviated chronic pain and depression.