Under the Influence of a Controlled Substance – California Health and Safety Code 11550
Strong Legal Representation for HSC 11550 Charges in California.
Under California Health and Safety Code 11550(a), it is a crime to use or be under the influence of a controlled substance without a valid prescription. A charge under 11550 HS does not require police to find any drugs on you. It is based on how you appeared to the officer and what a blood or urine test later showed. Most cases are misdemeanors, and many first-time defendants qualify for diversion that ends in a dismissal.
At The Law Offices of Arash Hashemi, our criminal defense attorney has spent over 20 years defending clients against drug charges throughout Los Angeles County. Attorney Hashemi will personally review your arrest, the officer’s observations and any chemical testing. Call (310) 448-1529 for a free, confidential consultation.
HS 11550 at a Glance
| Charge type | Misdemeanor (felony possible under HS 11550(e)) |
| Maximum jail | Up to 1 year in county jail |
| Probation | Up to 5 years |
| Repeat offenders | 180 days to 1 year with 2 or more prior convictions in 7 years and refusal of a drug program |
| Diversion | Often available under PC 1000 or Prop 36 |
| Drugs covered | Including methamphetamine, cocaine, heroin, fentanyl, PCP and many prescription opioids |
| Marijuana | Not covered |
Under the Influence of a Controlled Substance Under California Law
Health and Safety Code 11550 makes it unlawful to use or be under the influence of a controlled substance listed in the statute unless it was administered by or prescribed by a licensed medical provider. The statute does not require proof that you possessed any drugs at the time of the arrest. The charge is based on your physical and mental condition during the encounter and what that condition suggests about recent drug use.
Under the influence means the drug affected your nervous system, brain or muscles to an appreciable degree. A slight or minimal effect is not enough. HS 11550 does not apply to marijuana or alcohol. Driving while impaired by drugs is charged separately as a DUI under Vehicle Code 23152(f).
11350 vs 11550 HS: Understanding the Difference
HSC 11350 is a possession charge. The prosecution must prove you had a controlled substance in your actual or constructive possession, and physical evidence of the drug is required. Without the drug there is no case.
HSC 11550 is an impairment charge. No controlled substance needs to be found. A person who used drugs hours earlier, has nothing on them, and is stopped for an unrelated traffic matter can still be charged based on how they appeared to the officer and what a blood or urine test later revealed.
That structure makes the charge easier to file, but also more vulnerable to challenge. When the officer’s observations did not follow proper Drug Recognition Expert (DRE) protocol, when the symptoms have an innocent medical explanation, or when testing does not establish impairment at the time of the contact, the prosecution’s case can be undermined.
11550 HS Elements: What the Prosecution Must Prove
To secure a conviction, the prosecution must prove beyond a reasonable doubt that:
- You willfully used or were under the influence of a controlled substance
- The substance was one of the controlled substances listed in HS 11550
- You did not have a valid prescription for the substance
- You were under the influence to an appreciable degree at the time of the contact
The appreciable degree element is the most frequently contested. A DRE evaluation uses a 12-step protocol examining pulse, pupil size, muscle tone, injection sites and other physical indicators. When the protocol was not followed or the indicators have innocent explanations, the impairment finding can be challenged directly.
Penalties for an HSC 11550 Conviction in California
A violation of HS 11550(a) is a misdemeanor punishable by up to one year in county jail and up to five years of probation. There is no mandatory minimum jail term for a first or second offense, and the court can order a licensed drug treatment program in place of part or all of the jail time.
A 180-day minimum applies only under HS 11550(b), when you have two or more prior 11550 convictions within seven years and refuse to complete a drug program offered by the court.
When Is HS 11550 a Felony?
Under HS 11550(e), being under the influence of cocaine, cocaine base, heroin, methamphetamine or PCP while in immediate personal possession of a loaded, operable firearm is a wobbler. It can be charged as a misdemeanor or as a felony punishable by state prison. A second conviction under 11550(e) carries 2, 3 or 4 years in state prison. These cases often come with related charges such as possession of a controlled substance while armed (HS 11370.1).
Other Consequences
A conviction creates a criminal record that can affect employment, housing and professional licensing. For non-citizens, even a misdemeanor drug conviction can lead to serious immigration consequences, including deportation or denial of a green card.
Diversion and Dismissal Options for HS 11550
Many 11550 cases are resolved without a conviction. Under Penal Code 1000 pretrial diversion, eligible defendants complete a drug education or treatment program and the charge is dismissed. Prop 36 (2000) offers probation with treatment instead of jail for nonviolent drug offenses, and misdemeanor diversion under PC 1001.95 may be available at the judge’s discretion.
A dismissal through diversion avoids the consequences of a conviction, including the immigration risks. If you were already convicted, you may be able to clear your record through expungement under PC 1203.4 after completing probation.
How These Cases Are Built in Los Angeles
Most arrests begin with a traffic stop or a probation check where the officer observes signs associated with drug use. The police report typically describes pupil size, speech, balance, coordination and demeanor. A DRE-certified officer may conduct the 12-step evaluation, and a blood or urine test is then requested to identify the substance.
The gap between an officer’s subjective observations and a reliable finding of impairment is where most 11550 defenses are built. Officers are not always DRE certified, protocols are not always followed, and symptoms can come from medical conditions, fatigue or anxiety. Our criminal defense attorney examines every step from the initial stop through the chemical testing.
Legal Defenses Against HSC 11550 Charges
The Impairment Observation Was Not Reliable
When the officer’s observations did not meet DRE protocol standards, when the symptoms have innocent explanations, or when the officer was not qualified to conduct the evaluation, the impairment finding can be challenged. Diabetes, anxiety, neurological conditions and common medications can produce symptoms that an untrained officer mistakes for drug impairment.
The Chemical Testing Was Flawed or Insufficient
A positive blood or urine test does not by itself prove current impairment. Many drugs remain detectable for days or weeks after use. Our attorney challenges the testing method, the chain of custody, and whether the result actually shows you were under the influence at the time of the arrest.
The Stop Was Not Lawful
When the traffic stop or initial contact lacked reasonable suspicion, the evidence that followed can be suppressed, including the officer’s observations and any test results. An unlawful stop is often the most direct path to a dismissal.
Valid Prescription
If you had a valid prescription for the substance identified in testing and took it as directed, the use was lawful and the charge cannot stand.
Frequently Asked Questions About HS 11550
What does 11550(a) HS mean?
It refers to California Health and Safety Code section 11550, subdivision (a), the law against using or being under the influence of a controlled substance. On a police report or court record, “11550(a) HS M” means the charge was filed as a misdemeanor.
Is HS 11550 a felony?
Usually not. HS 11550(a) is a misdemeanor. It can be a felony only under HS 11550(e), when you were under the influence of certain drugs while holding a loaded, operable firearm.
Does HS 11550 apply to marijuana?
No. Cannabis is not one of the substances listed in HS 11550. Driving while impaired by marijuana can still be charged as a DUI.
Contact a Los Angeles Defense Attorney for HSC 11550 Charges Today
Attorney Arash Hashemi has defended clients against under the influence charges throughout Los Angeles County for over 20 years. He will review the circumstances of your arrest, the DRE evaluation and the chemical testing, and give you an honest assessment of every defense and diversion option in your case. You work directly with Attorney Hashemi from the first consultation through resolution.
Schedule a free Consultation:
- Phone: (310) 448-1529
- Email: Info@hashemilaw.com
- Address: 11845 W Olympic Blvd #520, Los Angeles, CA 90064
- Office Hours: Monday to Friday, 8:30 AM – 5:00 PM, with flexible scheduling options available, including weekend appointments.
We are conveniently located in the Westside Towers serving clients facing drug charges across Los Angeles, Beverly Hills, Santa Monica, the San Fernando Valley, Long Beach, and all surrounding communities. Your defense starts the moment you call.