Nearly five years after California legalized marijuana, a growing number of doctors and lawmakers are urging cannabis producers to warn consumers of the health risks associated with the drug, as part of proposed new rules to curb the commercial excesses of the market. They also want them to distribute health brochures to first-time customers outlining the risks cannabis poses to youth, drivers, and those who are pregnant—especially pot with high levels of THC, the psychoactive element of marijuana. More and more scientific studies point to an increased risk of developing psychiatric disorders, including schizophrenia, with such high-potency marijuana, compared with those who have never used it. Since legalization in California, emergency room visits for cannabis-induced psychosis rose 54 percent across the state, part of the reason why new rules would crack down on the commercialization and marketing of cannabis, along with adding caps on THC levels. The proposed rules are modeled after Canada, with rotating health warnings about risks to mental health, kids and teens, as well as brain development, and to those who are pregnant and breastfeeding. The pot industry, of course, considers such warnings “excessive” and expensive and says it would put "undue burdens" on marijuana businesses—all at the expense of ensuring public health. While California and other states should have considered the health implications of legalizing pot before legalizing and launching the new market, they can now take action to protect its most vulnerable populations.