The Global Tax Program Health Taxes Knowledge Note Series focuses on topics linked to implementation of health taxes, or excise taxes on tobacco, alcoholic drinks, and sugar-sweetened beverages. The purpose of this series is to provide policy makers with an overview of relevant issues and feasible policy choices in setting health taxes based on questions that emerge from the field during health tax reforms. This fourth brief in the series gives policy makers an overview of the revenue potential for health taxes, including from policy changes related to adjusting existing tax structures and rates. The knowledge note series is funded under the Health Tax Workstream of the World Bank's Global Tax Program: https://www.worldbank.org/en/programs/the-global-tax-program