Two men were hospitalized in Montgomery County on Thursday after they apparently were poisoned by smoking a legal herbal concoction that imitates marijuana, authorities said.

The two 19-year-olds vomited and suffered accelerated heart rates, said Blacksburg police Officer Greg Evans, who did not identify the men by name. One of them convulsed violently, Evans said.

One of the men is a Virginia Tech student and the other is from North Carolina and not affiliated with the university, he said.

An ambulance and police officers were called about noon to East Roanoke Street near Wharton Street in Blacksburg. An acquaintance took one of the men to Montgomery Regional Hospital, and the ambulance took the other one, Evans said.

They had been smoking Bayou Blaster, which is a type of legal herbal marijuana substitute, also known as "spice," that is made by blending herbs and spraying them with a synthetic marijuanalike drug. Spice is available in stores and online.

The American Association of Poison Control Centers said in a March news release that its centers -- including facilities in Virginia -- had received more than 100 spice-related calls since January 2009.

In March, Kansas became the first state to ban spice.

-- Jorge Valencia