This updated essay reviews research carried out since the start of the concept of healthcare regulation in Brazil and in the United Kingdom and how regulatory practices developed. The first study published more than a decade ago focused on economic regulation and the assessment of the quality of healthcare services provided by the Brazilian private market and the British National Health Service. This new version will discuss the main changes in both systems since the first edition of the “Legal and Forensic Medicine” in 2012, highlighting that economic regulation is no longer the main guideline for action in Brazil and in the United Kingdom. Beginning from a historical overview, the advent of regulatory authorities in both systems will be discussed, specially the Supplementary Health National Agency (a Brazilian agency, which has the acronym in Portuguese of “ANS”). As to the United Kingdom, the research sets out to cover briefly the legal framework supporting the powers and duties of different bodies within the National Health Service (NHS), with some remarks on the Health and Social Care Act 2022. The 2022 elections encouraged Brazilian politicians to enact populist laws, which were not adequately discussed with regulators or with the other stakeholders in the private health market. Coverage issues (with the inherent impact brought with the advent of Law 14454 in 2022) will also be assessed, as well as some remarks on the importance of the ANS list of medical procedures from the regulatory perspective. In Great Britain, the law underpinning the current public healthcare system will be discussed, with some statements on the private health insurance market.