A ban on the sale or possession of synthetic marijuana, so-called bath salts and salvia is now the law in Pennsylvania.
The law took effect Monday, two months after Gov. Tom Corbett signed a bill imposing the new restrictions.
Possession carries up to a year in jail and a $5,000 fine, while selling the substances could result in five years and a $15,000 fine.
Berks County District Attorney John Adams said last week that his office's drug task force was ready to enforce the new law and arrest those who don't comply.
"We are going to vigorously enforce this law, and we are notifying retailers today that we will be on your doorstep starting Monday morning," said Adams on Thursday.
Bath salts have been linked to cases of erratic or violent behavior, and until Monday were openly available at retail stores in Pennsylvania.
Adams said those who don't comply with the new law will be subject to criminal penalties similar to the possession of a controlled substance, such as cocaine and or marijuana.
Supporters of the new law said Pennsylvania's the 21st state to enact such a ban. New Jersey is among them.