Appellant was charged with cultivating marijuana in violation of Health & Saf. Code section 11358. His defense was medical need, i.e., “compassionate use.” The trial court instructed the jury on this defense in accordance with the Supreme Court’s opinion in People v. Mower (2002) 28 Cal.4th 457, that is, that the defendant had the burden of raising a reasonable doubt as to this defense. However, the court also instructed the jury that one of the “elements” of this defense was that “the defendant was seriously ill.” On appeal, the defendant argued that this latter instruction was prejudicial error, because the Compassionate Use Act as set forth in Health and Safety Code section 11362.5 does not require the defendant to prove that he was seriously ill. The Court of Appeal agreed and found the error reversible under both the Chapman and Watson standards of reversibility.