A spate of hospitalizations linked to synthetic "marijuana" led city officials to issue a warning Friday about the risk of consuming the herbal products that are often labeled as “incense” or “potpourri.” 

The Department of Health said there were over 150 emergency room visits linked to synthetic cannabinoid products between April 8 and April 15. An average of two to three emergency room visits related to the products were recorded for each day during the first few months of 2015.

Synthetic cannabinoids are herbal mixtures sprayed with chemicals that can create mind-altering effects if consumed. With brand names include “K2”, “Green Giant” and “Smacked!”, the products are often smoked. Side effects can include vomiting, seizures and even kidney failure and heart attacks. They are sold widely on the Internet and in head shops, but are illegal in New York City.  

The producers, which are difficult to identify, often label the packages with the warning "Not for human consumption." Nevertheless, YouTube videos and online reviews discuss the potency and flavor of the products when consumed. 

Ingredients are also sometimes listed on the packages, but health officials say it’s nearly impossible for consumers to tell what is really in the herbal mixtures.

The majority of the recent cases are in East Harlem, health officials said. The Health Department said it would issue reminders to local store owners to not sell the banned herbal products.