In contrast to previous studies that have focused on proximal outcomes such as access to and the utilization of healthcare, this study establishes and quantifies the influence of informal payments (IP) directly on population self-rated health, which can be considered the ultimate outcome. More specifically, we examine how making informal payments influences self-rated health by testing several theoretically-grounded explanations of the influence of making IP. Using the quasi-experimental instrumental variable technique increases the likelihood that our findings are not the result of reverse causality, omitted variable problem, and measurement error. Our main finding is that overall, making informal payments have a negative influence on self-rated health. However, this influence is higher for men, those who are poorer, live in rural areas, have a university education, and have lower social capital. Theoretical approaches that have stood out in explanations regarding the effects of making IP on self-rated health are Public Choice Theory, Institutional Theory, and Sociological Theories of Differences in Life Opportunities, Social Determinants of Health, and Social Capital.