At least 18 people in the Skid Row section of downtown Los Angeles fell ill and were hospitalized Friday after they smoked a tainted batch of fake marijuana known as Spice, a medical doctor said.

The Los Angeles Fire Department got the first call around 10 a.m.

“We started receiving calls about people who had ingested something,” said LAFD Public Information Officer David Ortiz.

Paramedics responded to the corner of 5th and Wall streets, where many homeless people camp out. The Fire Department blocked off the area as victims were treated.

“They were all exhibiting similar symptoms of various levels,” Ortiz explained.

Ten people were transported to Los Angeles County-USC Medical Center where they were agitated or else appeared sedated, said Dr. Michael Levine, director for toxicology at the hospital.

He said the patients said they had taken Spice.

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The fake cannabis is a designer drug in which different herbs or plant shrubs are sprayed with lab-made liquid chemicals to mimic the effect of tetrahydrocannabinol or THC. The street drug is sold under names such as Scooby Snax, K2, Paradise and Black Magic.

Levine said doctors began to see patients under the influence of Spice five years ago.

“Other than this incident today, we’re not seeing a ton more,” he added.

But, the number of people sickened at once on Friday was unusual.

LAFD spokesman Brian Humphrey said the department averages about a dozen health-related calls a day to Skid Row, so the mass sickness was cause for concern.

“In this case, we had nearly two dozen all in one location.”

Humphrey said the term “overdose” didn’t do justice to the danger of street drugs.

“Any dose of a street substance is too much,” he said. “There’s always someone out there looking to change the product.”

The Rev. Andy Bales, who heads the Union Rescue Mission, said drugs are a major problem on Skid Row. “As long as we have people on the street in that brutal reality, they’re going to be looking for an escape,” Bales said.

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He said unscrupulous dealers take advantage of the homeless, with some even going as far as “setting up tents” so they can blend in with the Skid Row population.

As Bales explained, Spice is a cheap high — the equivalent of a last resort.

“It’s usually a dollar a hit,” he said.

Outside the Downtown Women’s Center — an organization dedicated to helping women overcome homelessness — the Skid Row illnesses were all anyone was talking about.

Pam Walls said she used to be homeless, but now works at the center.

According to Walls, Spice is widely used in the area.

“You breathe it in and it burns your nostrils,” Walls said.

She believes it was an especially potent batch of the drug that made the victims sick.

“It’s not like regular Spice; this is 100 times more potent,” Walls said.

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Friday wasn’t the first time Spice had sickened a large group of people on Skid Row.

In April, a dozen people living in the area were taken to area hospitals after smoking the drug.

Carol Elston has lived downtown since November, primarily at the Union Rescue Mission. She said she sees people smoking Spice all the time and knows the distinctive smell.

“It smells like skunk,” Elston said.

She added that she can tell when people smoke it because of their appearance.

“They look like zombies,” Elston said.

Digital News Editor Ryan Fonseca contributed to this report.