Cal. Welf. & Inst. Code § 5213

(a) If, upon evaluation, the person is found to be in need of treatment because the person is, as a result of a mental health disorder, a danger to self or others, or is gravely disabled, the person may be detained for treatment in a facility for 72-hour treatment and evaluation. Saturdays, Sundays, and holidays may be excluded from the 72-hour period if the State Department of Social Services certifies for each facility that evaluation and treatment services may not reasonably be made available on those days. The certification by the department is subject to renewal every two years. The department shall adopt regulations defining criteria for determining whether a facility may reasonably be expected to make evaluation and treatment services available on Saturdays, Sundays, and holidays.
(b) Persons who have been detained for evaluation and treatment, who are receiving medications as a result of their mental illness, shall be given, as soon as possible after detention, written and oral information about the probable effects and possible side effects of the medication, by a person designated by the mental health facility where the person is detained. The State Department of Social Services shall develop and promulgate written materials on the effects of medications, for use by county mental health programs as disseminated or as modified by the county mental health program, addressing the probable effects and the possible side effects of the medication. The following information shall be given orally to the patient:
1. (1) The nature of the mental illness, or behavior, that is the reason the medication is being given or recommended.
2. (2) The likelihood of improving or not improving without the medications.
3. (3) Reasonable alternative treatments available.
4. (4) The name and type, frequency, amount, and method of dispensing the medications, and the probable length of time that the medications will be taken.
(c) The fact that the information has or has not been given shall be indicated in the patient’s chart. If the information has not been given, the designated person shall document in the patient’s chart the justification for not providing the information. A failure to give information about the probable effects and possible side effects of the medication does not constitute new grounds for release.