California Code, Health and Safety Code - HSC § 11110

(a) It shall be an infraction, punishable by a fine not exceeding two hundred fifty dollars ($250), for any person, corporation, or retail distributor to willfully and knowingly supply, deliver, or give possession of a drug, material, compound, mixture, preparation, or substance containing any quantity of dextromethorphan (the dextrorotatory isomer of 3-methoxy-N-methylmorphinan, including its salts, but not including its racemic or levorotatory forms) to a person under 18 years of age in an over-the-counter sale without a prescription.

(b) It shall be prima facie evidence of a violation of this section if the person, corporation, or retail distributor making the sale does not require and obtain bona fide evidence of majority and identity from the purchaser, unless from the purchaser's outward appearance the person making the sale would reasonably presume the purchaser to be 25 years of age or older.

(c) Proof that a person, corporation, or retail distributor, or his or her agent or employee, demanded, was shown, and acted in reasonable reliance upon, bona fide evidence of majority and identity shall be a defense to any criminal prosecution under this section. As used in this section, “bona fide evidence of majority and identity” means a document issued by a federal, state, county, or municipal government, or subdivision or agency thereof, including, but not limited to, a motor vehicle operator's license, California state identification card, identification card issued to a member of the Armed Forces, or other form of identification that bears the name, date of birth, description, and picture of the person.