SACRAMENTO — 

California Gov. Gavin Newsom vetoed a bill Saturday that would have decriminalized the possession and personal use of a short list of natural psychedelics, including “magic mushrooms.”

The Democratic governor said that while he supports “new opportunities to address mental health through psychedelic medicines like those addressed in this bill,” the state needs to establish regulations for the use of these substances before they are legalized.

“California should immediately begin work to set up regulated treatment guidelines — replete with dosing information, therapeutic guidelines, rules to prevent against exploitation during guided treatments, and medical clearance of no underlying psychoses. Unfortunately, this bill would decriminalize possession prior to these guidelines going into place, and I cannot sign it,” Newsom said in his veto statement.

Sen. Scott Wiener (D-San Francisco), the bill’s author, said the veto “is not the end of our fight,” and pledged to reintroduce legislation for next year that would focus on the therapeutic use of the psychedelics, as Newsom requested.

“This is a setback for the huge number of Californians — including combat veterans and first responders — who are safely using and benefiting from these non-addictive substances and who will now continue to be classified as criminals under California law,” Wiener said. “Today’s veto is a huge missed opportunity for California to follow the science and lead.”

Wiener previously told The Times that the state lacks reliable data on arrests for possession