Thailand became the first Asian country to decriminalize marijuana, an unusual step in a region known for harsh drug laws and punishment for drug trafficking, including the death penalty in Singapore. The government said the goal was to jumpstart the country’s participation in the multibillion-dollar medical-cannabis industry and give people more freedom to make healthcare decisions. But the legislature failed to establish market rules and regulations, giving entrepreneurs a green light to sell a wide range of products, from cannabis-infused cocktails and curries to exotic strains with a wide range of supposed benefits—relaxation, sexual arousal, energy boosting, and boosting creativity. While lawmakers have since rushed to issue directives to limit sales to pregnant women and anyone under 20, as well as smoking in public, the takeaway for consumers was that recreational use was now legal. Meanwhile, cannabis sellers are thriving in the chaotic situation, in which a doctor’s note is not required—unlike medical cannabis markets in the U.S.—and products are promoted without any scientific backing or warnings. As more U.S. states legalize weed, the situation in Thailand is a cautionary tale of what governments must do to protect public health before they establish a cannabis market.