The U.S. Food and Drug Administration is concerned about “unscrupulous” clinics who are selling stem cell treatments that can’t be guaranteed for efficacy or safety, and have issue a new warning that they are cracking down on the practice. Many clinics nationwide have been selling stem cell therpaies that have not be verified by the FDA, and the agency intends to put an end to it.

The FDA has already starting acting against clinics in Florida and California, sending a warning to the US Stem Cell Clinic in Sunrise, Fla., for marketing stem cell products that hadn’t been approved by the FDA. The clinic reportedly claims that it can use stem cells from a person’s fat to treat many conditions like Parkinson’s Disease. The clinic has been linked to cases of blindness.

However, some clinics are fighting back. IN an interview with Shots, Elliot Lander, medical director of the California Stem Cell Treatment Centers, criticized the move.

“I think it’s egregious,” Lander says, arguing that in many cases they are developing treatments and aren’t profiting. “I think they made a mistake. I’m really baffled by this. … Nobody was charged a single penny. We’re just trying to move the field forward.”