Gov. Jerry Brown has signed a bill prohibiting the production and retail sale of caffeinated beer, making California the seventh state to do so.
Critics say the beverages are aimed at young people and make it easy to drink too much. They typically come in large containers, with high alcohol content and sweet, fruity flavors.
The drinks drew scrutiny after incidents in which college students drank too many, some requiring hospitalization.
The bill's author, Democratic state Sen. Alex Padilla of Los Angeles, says the beverages are a threat to public health because they can mask the effects of alcohol. Brown announced he had signed SB39 on Monday.
Most manufacturers have changed their formulas to exclude caffeine.