The new drug “spice” — a type of synthetic marijuana — is causing a worrying increase in hospitalizations.

Poison centers in the United States received 1,900 calls from people who were having adverse reactions to “spice,” which is four times the number of calls the same period just a year ago, according to a USA Today report.

New York Gov. Andrew Cuomo issued a health alert on April 17 after the state received 160 patients in just nine days. About 317 synthetic marijuana-related emergency visits happened in an 18-day window in Alabama, according to the report. Other states also reported sudden increases in reports of the synthetic cannabinoid.

Experts think that there may be a “new batch” of some sort out there that is causing the emergency room visits.

Packets of “spice” are often found at gas stations, typically labelled as incense or potpourri with a warning that it is not for human consumption. However, users smoke it, which is typically a drug that is sprayed on plant leaves.

It gained popularity back in 2009, resulting in a ban by federal and state regulators, but manufacturers have been able to get around the ban by altering the formula.

The drug can cause the patient to stay in the emergency room for a while and require muscle relaxers to keep them calm. People think that the drug is safe because they think it’s just a different type of marijuana, but the drug can often be laced with other dangerous substances.

Overdose symptoms include kidney failure, rapid heartbeat, and hallucinations.

A total of 26 types of synthetic drugs have been banned by the feds, but by simply changing one molecule, chemists can get around the ban.

A total of 43 states have taken action against synthetic cannabis. Despite that, synthetic drugs have been growing rapidly, with 51 different kinds discovered in 2012 compared to just two in 2009.