Brazil?s Digital Child and Adolescent Act (2025) prohibits paid loot boxes in games accessible to minors under a public health and child-rights framework, regardless of whether they should be classified as gambling. The law focuses on psychological mechanisms underlying harm, including variable-ratio reinforcement and reward uncertainty, to which adolescents are developmentally vulnerable. It establishes administrative sanctions, including fines of up to 10% of the company?s revenue and service suspension, and restricts personalized advertising and algorithmic systems targeting minors. As the first major market to adopt a preventive harm-reduction ban, Brazil creates measurable regulatory benchmarks and a natural experiment to assess whether legislative boundaries reduce harm, influence industry monetisation strategies, and inform proportionate digital governance internationally.  Kulcsszavak: gambling, adolescent, public health, loot boxes, video games, child welfare, Brazil, gaming disorder, policy, regulation