Wen said the drugs are often marketed as natural but contain untested chemical compounds that can harm or kill. People who use synthetic marijuana play "Russian Roulette" because they don't know what they are taking, Wen said in a statement.
Synthetic marijuana is also sold as synthetic cannabinoids, K-2, fake or legal weed, spice and genie. The products are usually herbs and spices with a synthetic compound similar to the psychoactive ingredient in marijuana. They're often sold as incense and labeled "not for consumption."
The city health department will pass out information about the dangers and warning signs of the drugs. Wen also urged parents to talk to kids about the dangers.
She joins officials from the Maryland Health Department and the Maryland Poison Center at the University of Maryland School of Pharmacy in advising against taking the drugs.
"We want to warn all of our residents of the warning signs of someone who may have taken synthetic cannabinoids, and urge anyone who witnesses these symptoms to call 911 or take the individual to the ER immediately," Wen said.
Public health officials throughout the state are worried because synthetic marijuana can kill. Three people in Chicago died after taking the drugs, and dozens of others there have also suffered from bleeding.
Rat poison was found in batches of the drugs in Chicago. Maryland officials still are investigating if that is the case in Maryland.
There have been no deaths in Maryland, where three of the victims were from the central part of the state and the fourth from the west. Further details about the victims have not been released because of privacy laws.
Signs of synthetic marijuana include nosebleeds, bleeding of the gums, bleeding out of proportion to the level of injury, vomiting blood, blood in the urine or stool, excessively heavy menstrual bleeding, and back pain.