Do differences in health literacy contribute to the widely documented health-income gradient? In the context of Sweden, we document a strong relationship between exposure to health-related expertise — captured by the presence of a health professional in the family — and health. Exposure to expertise raises preventive health investments throughout the lifecycle, improves physical health, and prolongs life. Two quasi-experimental research designs — admissions lotteries into medical school and variation in the timing of medical degrees — support a causal interpretation of these effects. We estimate that unequal exposure to health-related expertise may account for up to 18 percent of the population-wide health-income gradient.