The 18-year-old was recently spotted smoking the legal drug salvia divinorum and sales have increased up to three times in some places.
According to TMZ, several stores in LA have seen sales radically increase and some people have even asked for 'the stuff Miley was smoking' when they into the stores.
One shop employee said to the US website: "Salvia is one of those things that you only try once because it is so intense."
There has been discussions about banning the drug in California as it is already illegal in 15 states.