This study compared prescription sales data from a large retail pharmacy chain in the United States with Google Flu trends and US Outpatient ILI Surveillance Network data for 2007 by Centers for Disease Control and Prevention as a flu activity indicator. For Google trends the correlation coefficient (Pearson ‘r’ ) for five years aggregate data (2007-2011) was 0.92 (95% CI, 0.90-0.94, P = 0.05) and for each of the five years between 2007 and 2011 were 0.85, 0.92, 0.91, 0.88, and 0.87 respectively. For CDC data the same was 0.97 (95% CI, 0.95-0.98, P = 0.05).