Umbrella branding is a marketing practice whereby multi-product firms leverage their reputation across different product categories. The paper investigates how advertising in the market for non-prescription drugs affects the decision to buy prescription drugs from the same firm. To estimate the effects of umbrella branding, I exploit the fact that consumer-directed advertising of prescription drugs is prohibited in Germany and identify advertising spillovers with an instrumental variable that builds on exogenous seasonality in the non-prescription drug industry. Umbrella branding results in market expansion, particularly for generic firms, and can have a positive effect on consumer welfare in under-treated therapeutic areas.