They're wrapped in packages with labels like 'Spice' and 'K2'. Others are being marketed as 'Bath Salts', but synthetic drugs on sale in corner stores has law enforcement annoyed.
Just ask police officer Dave Northway.
"We can only do what the law allows us to do," he said. "If it says just these substances, they're the only ones that we can enforce. If the people who are making these come out with something new that gets around that, we have no way to stop that."
Synthetic drug companies based mainly in Europe and Asia are changing the chemical makeup of the drugs' main ingredient, called a 'base compound'. When they're done, the drug is every bit as potent but it's no longer illegal.
The loophole's become a big impediment to law enforcement efforts to crack down on synthetic drugs, but tightening it could become a big impediment to your health.
Many of the base compounds are used in everyday, legal pharmaceuticals. With lawmakers already talking about banning more base compounds, it's up to Dave Gross at the Florida Department of Law Enforcement to figure out the potential impact.
He says only a sliver of all the compounds out there are actually used in common drugs, and the goal now is to come up with that list.
"What we do is, we ensure through intelligence, talking to other states, talking to other countries, that the use for the substances that we're going to ban has no other purpose than an illegal purpose," Gross said.
But that may give the synthetic drug companies just enough leeway to find a new way around the law, slowing but not stopping a troubling epidemic.
The legislature passed a ban on the mis-marketed bath salts last year. Earlier this year they passed another ban on more than 90 compounds that are mostly used in producing synthetic marijuana.