The law says you can carry around quite a bit of prescription drugs, provided they were legally prescribed for you. There may be an issue if you're carrying an excessive quantity of a controlled substance, such as a year's supply. That much could easily be construed as being for distribution, not for personal use.

Here's an interesting point from the linked article:

The below sentencing memorandum, filed yesterday (12/2) by deputy district attorney Ann Rundle, also asks Judge Elden Fox (who is scheduled to sentence Ryder this Friday) to order the actress to serve 480 hours of community service and to cease using aliases, specifically the handle "Emily Thompson." When the 31-year-old actress was arrested last December for shoplifting, Beverly Hills cops found Ryder carrying a remarkable array of painkillers (liquid Demerol, Percodan, Vicodin, Morphine Sulfate, etc.), some of which were prescribed to the Thompson alias.

It appears she used an alias to get prescription drugs, specifically very powerful and highly regulated pain killers. From what I understand, that's illegal. The 2nd page of the criminal complaint states:

On December 21, 2001, defendant Ryder was arrested at Saks Fifth Avenue in Beverly Hills on the charge of felony grand theft. During the booking procedure, Beverly Hills Police discovered the following narcotics in her possession: liquid Demerol, liquid Diazepam, Vicoprofen, Vicoden, Percodan, Valium, Morphine Sulfate and Endocet (containing Oxycodone).



Investigating Officer Elwell was later able to confirm prescriptions for all of the narcotics with the exception of the Endocet tablets. The prescriptions obtained were from several different physicians and the defendant had utilized at least 2 different names in obtaining them (including Emily Thompson).

On February 1, 2002, defendant Ryder was charged with Commercial Burglary, Grand Theft, Vandalism and Possession of a Controlled Substance (Oxycodone), all felonies. Just prior to trial, the defense presented a declaration from a physician admitting that he had provided the Endocet (generic form of Oxycodone) the the defendant without a prescription as part of claimed treatment. In light of this claim, the People moved to dismiss that count in the interest of justice.



My wife is the Nurse Manager of a pain clinic. She's told me several times of the regulations they have to comply with in their practice. The fines for a single infraction can easily top $10,000. An infraction could easily be something as minor as a paperwork error but the fines can still be enormous. This is serious stuff.