The actor believes there is a link between vaccines and autism. He branded California Gov. Jerry Brown a "corporate fascist" after he signed into law one of the strictest immunization programs in the country earlier in the day.
In a series of more than half a dozen tweets that ended in a flurry of capital letters, the Golden Globe winner insisted he was "pro-vaccine." He was only "anti-neutrotoxin," he said, repeating his claim that ingredients such as thimerosal and mercury carry a risk to children.
Carrey has been an activist on the issue since his relationship with Jenny McCarthy, the model, actor and author who believes her son's autism was caused by vaccines.
Despite lingering fears among some parents, the Centers for Disease Control and Prevention is clear that there is no link between vaccines and autism. Echoing the broad scientific consensus, the CDC says there is "no link between thimerosal-containing vaccines and [autism], as well as no link between the measles, mumps, and rubella (MMR) vaccine and [autism] in children."
During his Twitter sermon late Tuesday, Carrey also took aim at the CDC, calling it "corrupt" and unable to "solve a problem they helped start."
The California law comes in the wake of a measles outbreak at Disneyland last year that affected more than 100 people in the U.S. and Mexico. The state joins West Virginia and Mississippi as the only states without a personal-belief exemption for vaccines, according to The Associated Press.
"The science is clear that vaccines dramatically protect children against a number of infectious and dangerous diseases," Brown wrote in a message accompanying his signature. "While it's true that no medical intervention is without risk, the evidence shows that immunization powerfully benefits and protects the community."
This story originally appeared on NBCNews.com