Observational studies of oseltamivir and influenza complications could suffer from residual confounding. Using negative control risk periods and a negative control outcome, we examined confounding control in a claims-based study of oseltamivir and influenza complications (pneumonia, all-cause hospitalization, antibiotic dispensing). Within the FDA's Sentinel System we identified individuals ≥18 years initiating oseltamivir on the influenza diagnosis date versus those who did not, during three influenza seasons (2014-2017). We evaluated primary outcomes in the following 1-30 days (primary risk period) and 61-90 days (negative control period), and non-vertebral fractures (negative control outcome) in days 1-30. We estimated propensity score-matched risk ratios (RR) per season.