California Code, Business and Professions Code - BPC § 2220.5

(a) The Medical Board of California is the only licensing board that is authorized to investigate or commence disciplinary actions relating to physicians and surgeons who have been issued a certificate pursuant to Section 2050.

(b) For purposes of this section, “investigate or commence disciplinary actions” shall mean written, oral, or telephonic communication with a physician or surgeon concerning his or her violation of the Medical Practice Act or any other provision of this division.

(c) Written complaints that are subject to Section 43.96 of the Civil Code, relating to the professional conduct or professional competence of physicians and surgeons, shall be processed in accordance with that section.