London, UK - They looked like ordinary gummy bears, but these powerful candies were not the average sweet treat.

London high schoolers were hit hard by an additive that had been mixed into their candy: cannabis!

The Catholic school teens experienced serious side effects during class and were rushed to the emergency room on March 12, the Daily Mail reported.

London police are now warning parents about the dangerous product.

"These sweets are not what they appear to be," officials said. "Sadly, a number of school pupils in Sutton have been either made very ill or hospitalized as a result of eating them."

They warned that eating the treats could have an effect similar to smoking marijuana, but that it was hard to manage because it was being consumed in larger quantities by eating.

The gummies had not yet been fatal, but led to serious effects like panic attacks, dizziness, and vomiting.

This was not the first time that the unusual gummy sweets were circulated at an English school.

Thirteen girls were hospitalized in a similar incident at a nearby Catholic school last October after eating gummies laced with THC – the active ingredient in cannabis.

The students had bouts of dizziness and vomited while in class, according to their teacher.

Cannabis is currently only licensed in the UK for medicinal purposes and is illegal for recreational use.