California has a long history of enacting and enforcing strong consumer protection laws. Product advertising and labeling must be truthful about information a customer would find important in making a purchase, for example, how well a product will perform, where it is made, how long it will last, what ingredients it has, how healthy it is, and whether it really "on sale." California also has an Unfair Competition Law that allows affected individuals to sue companies that violate other laws when they sell their products (for example, if the product contains a toxic ingredient) on behalf of the general public.
CALIFORNIA UNFAIR COMPETITION LAW
California Bus. & Prof. Code § 17200
CALIFORNIA CONSUMERS LEGAL REMEDIES ACT
California Civ. Code § 1750
CALIFORNIA FALSE ADVERTISING LAW
California Bus. & Prof. Code § 17500