Health officials are alarmed about a sharp rise in ER visits and calls to poison control centers about a street drug called “Spice.”

The drug is sold under a variety of names as incense. But experts say it’s synthetic marijuana and can be 100 times more potent.

Poison Control Centers received about a thousand calls about troubling reactions to spice in the first three weeks of April alone. That’s more than double the number of calls received since the beginning of the year.

Spice users may experience delusions, extreme anxiety and become violent. It’s also been implicated in several deaths.