Mississippi and Alabama 'Spice' Overdoses Send More Than 300 to ER in 2 Weeks

Synthetic marijuana sends people to the hospital in Mississippi and Alabama.

In the short term, symptoms include seizures, hallucinations, increased heart rate, suicidal thoughts, anxiety attacks and uncontrollable rage, he said. The long-term effects are unknown.

Health officials warned that spice contains "unpredictable" chemicals that are not natural and can also result in a coma.

Spice is meant to mimic tetrahydrocannabinol ,or THC, the chemical found in cannabis. Although it's marketed as "natural," it's anything but.

The DEA has found it's rarely mixed in a lab. Instead, they've found distributors concocting synthetic pot in animal feed troughs, on tarps in their garages and in storage units, she said.

The packets have several different brand names, including Mr. Smiles, Black Mamba, K2 and Spice, she said. But even within the same brand, the plant materials are often sprayed with different chemicals.

"The one overriding message on these things is that you don't know what you’re getting," Carreno said. "There's no consistency in the chemical in it, and there's no consistency in potency of the chemical that's in it."