I concur in the majority’s judgment, but I disagree sharply with certain of its intermediate conclusions. To place my views in context, I briefly review the facts and procedural background.
In 2001, defendant was arrested while transporting one pound three ounces of marijuana in his pickup truck. Officers stopped the truck on a tip and confirmed that it “reeked” of marijuana. Defendant twice denied there was marijuana in the tmck. Yet a search of his backpack, which had been located on tiie passenger seat, revealed numerous baggies containing premeasured amounts of marijuana. The backpack also contained an electronic scale. Further searching revealed a one-pound brick of marijuana concealed in a storage compartment behind the passenger seat. 1 The truck contained no paraphernalia for personal use.
Defendant was charged with transporting marijuana (Health & Saf. Code, § 11360, subd. (a))2 and possession of marijuana for sale (§ 11359). During his 2002 trial, at a hearing under Evidence Code section 402, he sought an instruction asserting, as to both charges, a defense authorized by the Compassionate Use Act of 1996 (CUA; § 11362.5). At the time of defendant’s trial, this defense expressly applied only to medical patients who possessed or cultivated marijuana “for [their] personal medical purposes” upon a physician’s recommendation or approval. (Id., subd. (d).) However, Courts of Appeal had split on the issue whether the defense implicitly extended to an eligible patient’s transportation of marijuana for personal medical use.
*101At the hearing, defendant offered testimony that he was an eligible patient who was transporting amounts necessary and reasonable for his particular needs. He also testified that he actually was transporting the marijuana for his personal medical use. The court nonetheless refused the instruction. It ruled that the CUA defense did not apply to a charge of possession for sale, and was also not appropriate for the transportation of “one pound, three ounces of marijuana.” However, the court permitted defendant to put on evidence that the marijuana was for his personal use as proof he did not possess it with intent to sell. After the defense presented its case at trial, defendant renewed his request for CUA defense instructions. The request was again denied.
Defendant was convicted on both counts. The Court of Appeal reversed, concluding that the trial court’s failure to instruct on the CUA defense was prejudicial error as to both convictions. We granted the People’s petition for review. Our initial aim was to resolve the Court of Appeal conflict on the application of the CUA defense to a charge of transporting marijuana. While review was pending, however, the Legislature adopted the Medical Marijuana Program (MMP; § 11362.7 et seq.), which expressly extends a CUA defense to the marijuana crimes of transportation, and possession for sale, insofar as the marijuana was possessed and/or transported by an eligible patient for his or her personal medical purposes. (§ 11362.765, subds. (a), (b)(1).)
The majority holds that the MMP applies retroactively to defendant’s case. It further determines that the trial court “erred” by failing to instruct on the CUA defense now authorized by the MMP, because defendant adduced evidence sufficient to raise a reasonable doubt concerning both his medical eligibility to use the quantity of marijuana with which he was arrested, and his actual intent to use it only for his personal medical purposes. However, the majority concludes, this “error” was harmless, because the jury necessarily rejected any CUA defense when, under proper instructions defining the offense of possession for sale, it convicted him of that charge.
I acknowledge that the MMP extends a limited CUA defense to the particular charges defendant faced. I also concur in the majority’s holding that the MMP applies retroactively to defendant’s case. I further agree that, even if the MMP technically would have warranted a CUA defense instruction on either or both the charged offenses, no retrial is necessary. As the majority indicates, defendant’s conviction of possession for sale, upon instructions that correctly defined all the elements of that offense, proves that the absence of a CUA defense instruction did not affect the trial outcome.3 *102Additionally, however, I conclude, contrary to the majority, that defendant did not produce enough evidence to justify an instruction on the CUA defense pursuant to the MMP.
As the majority concedes, the CUA defense authorized by the MMP has three prongs, and defendant would not have been entitled to an MMP instruction on the defense unless he raised a reasonable doubt with respect to all three. Upon his failure to do so, the trial court, in the exercise of its “gatekeeping” function (see People v. Mower (2002) 28 Cal.4th 457, 475-476 [122 Cal.Rptr.2d 326, 49 P.3d 1067]; People v. Jones (2003) 112 Cal.App.4th 341, 350 [4 Cal.Rptr.3d 916] (Jones); see also People v. Lucas (1995) 12 Cal.4th 415, 466 [48 Cal.Rptr.2d 525, 907 P.2d 373]), could and should have ruled that the evidence was insufficient to allow the defense to go to the jury.
Thus, to justify a CUA defense instruction under the MMP, defendant must have adduced creditable evidence, first, that he was a “qualified patient,” in that a licensed physician had recommended or approved his personal use of marijuana to treat a condition specified in the CUA (see §§ 11362.715, 11362.765, subds. (a), (b)(1)), second, that the quantity possessed or transported, to the extent it exceeded eight ounces of dried marijuana, was consistent with his particular medical needs, as approved by a physician (§ 11362.77, subds. (a), (b)), and third, that the marijuana on which the charges are based actually was “for his . . . own personal medical use” (§ 11362.765, subd. (b)(1)).
I am persuaded defendant did not satisfy this minimal burden as to any of the prongs of the defense. Defendant’s proffered evidence that he was a qualified medical marijuana patient at the time of his arrest was extremely weak. At the Evidence Code section 402 hearing, Dr. Richard Eidelman testified he had twice given written approval for defendant’s medical use of marijuana. At trial, both defendant and Dr. Eidelman reiterated this claim.4 However, these writings were not produced. Though written approval is not required, this lapse undermines the credibility of the “qualified patient” claim. Moreover, as the officers had testified, defendant, when arrested, did not identify himself as a medical marijuana patient, and he denied the presence of marijuana in his tmck, thereby suggesting consciousness of guilt.
Under proper circumstances, bare testimonial assertions of a physician’s approval may be sufficient evidence of the defendant’s status as a qualified *103patient. (Jones, supra, 112 Cal.App.4th 341, 350-351.) Here, however, such claims simply evaporate in light of the powerful contrary indicia that defendant was not a qualified user who was transporting marijuana for legitimate purposes.
Even more deficient was defendant’s evidence that he had medical approval to possess quantities in excess of eight dried ounces. Both defendant and Dr. Eidelman testified that the first of Dr. Eidelman’s two written approvals, issued prior to defendant’s arrest, was for an unspecified “self-regulating dosage.” In my view, such a vague and open-ended authorization fails, as a matter of law, to constitute the specific determination the MMP requires—i.e., “a doctor’s recommendation that [eight dried ounces] does not meet the qualified patient’s medical needs.” (§ 11362.77, subd. (b), italics added.)
As defendant and Dr. Eidelman further testified, it was only after the arrest that defendant obtained Dr. Eidelman’s second approval, which conveniently endorsed the specific amount of marijuana that already had been found in defendant’s backpack and truck. But, for obvious reasons, absent “ ‘exigent circumstances’ ” not present here, the CUA defense cannot apply to a physician’s postarrest ratification of self-medication on marijuana. (People v. Rigo (1999) 69 Cal.App.4th 409, 412 [81 Cal.Rptr.2d 624]; see also People v. Trippet (1997) 56 Cal.App.4th 1532, 1548, fn. 13 [66 Cal.Rptr.2d 559].)
Finally, I conclude, the overwhelming evidence that defendant possessed the marijuana with the intent of selling it precluded a reasonable doubt as to its personal medical purpose. This evidence prominently included the electronic scale, the presence of which defendant never explained.
Moreover, as Justice Sills aptly observed in his dissent below, the marijuana at issue here was not found in “one large bag . . . , as one would expect... if it was for a single individual’s personal use. [On the contrary], it was found in nine different portions: Two very large baggies, each containing 30.6 grams of marijuana, seven small baggies in approximately equal amounts [,] and a large ‘brick’ of [marijuana] wrapped in a shirt which weighed about a pound. Six of the small baggies were located in a black bag along with [the] electronic scale. The brick was found [secreted under] the truck’s back seat; the large baggies were found in [defendant’s] backpack but not in the same section with the scales and the small baggies of marijuana. It is particularly noteworthy that [defendant] was carrying a single small baggie of marijuana in his pocket, separate from all the other parcels, as if that were his personal property as distinct from the large supply available for distribution.”
*104Sergeant Cuadras, an experienced narcotics officer who participated in the search and arrest, gave his expert opinion that the marijuana was for sale, not for personal use. He based this opinion, inter alia, on the way the marijuana was packaged, the large amount of marijuana concealed in the truck’s storage compartment, and the presence of the electronic scale.
The MMP recognizes the possibility that, with specific medical approval, qualified patients may be entitled to handle significant amounts of dried marijuana for their personal medical use. (See § 11362.77.) Yet the overwhelming evidence detailed above essentially negates an inference that defendant was transporting this very large quantity of marijuana under such circumstances.5 In sum, his evidence of personal medical use failed to establish, for purposes of entitlement to a CUA instruction, a reasonable doubt that he possessed and transported the marijuana with intent to sell it.
Accordingly, I conclude, an instruction on the CUA defense was not warranted under the MMP, and the trial court’s ruling to that effect would have been correct. On this basis alone, I would reverse the Court of Appeal’s judgment and reinstate defendant’s convictions.
One additional point warrants comment. The majority consistently applies the term “error” to the trial court’s instructional rulings, even though the majority relies solely on statutory law that was not in effect when the trial court acted. Of course, we do not expect clairvoyance from our courts. Indeed, a judicial ruling that departed from then-current law would itself be error. Thus, even assuming a CUA instruction was warranted, nunc pro tunc, by virtue of the later-enacted MMP, I would not imply criticism of a diligent and hard-pressed trial court by labeling its failure to anticipate this statute as “error.”
Instead, it is sufficient to determine, in hindsight, whether the MMP, as retroactively applied, justified a CUA instruction in defendant’s case, and, if so, whether the absence of the instruction influenced the outcome, thus rendering the trial unfair by current standards. If the answer is “yes,” we can and should simply remand for a new trial, without citing trial court “error” as the reason.
*105As indicated, I, unlike the majority, do not believe the MMP would justify a CUA instruction on the facts of this case. Assuming, however, that the majority is correct on that point, I agree, for the reasons expressed in its “harmless error” analysis, that omission of the instruction did not affect the trial outcome, thus rendering the trial unfair. I therefore concur in the judgment of reversal.
On December 20, 2006, the opinion was modified to read as printed above.
According to an August 30, 2006, press release by the White House Office of National Drug Control, the current street value of a pound of marijuana is about $4,000. (White House Off. of Nat. Drug Control, Press Release (Aug. 30, 2006); online at <http:www.whitehousedrugpolicy.gov/about/index.html> [as of Nov. 27, 2006].) On that assumption, defendant was arrested while transporting marijuana with a street value of about $4,750.
All further unlabeled statutory references are to that code.
Indeed, the jury found defendant possessed the marijuana with intent to sell it despite hearing defendant’s evidence that the marijuana was for his personal medical use, as approved by a physician.
The majority notes defense counsel argued that the testimonial evidence that Dr. Eidelman approved defendant’s medical use of marijuana was “uncontroverted.” (Maj. opn., ante, at p. 88.) However, both at the Evidence Code section 402 hearing, and at trial, the court allowed the prosecution to impeach Dr. Eidelman’s credibility with evidence that he was then under investigation by the California Medical Board for numerous alleged violations of the Business and Professions Code in connection with his license to practice medicine in this state.
The majority notes defendant testified that the large quantity was necessary and reasonable because he preferred to eat, rather than smoke, marijuana. However, Sergeant Cuadras testified that in his experience he had never encountered someone transporting a pound and three ounces of marijuana for the purpose of eating it.