The consumption of medication, especially over-the-counter (OTC) drugs, can reflect environmental exposure with a lesser degree of severity in terms of morbidity. The non-linear effects of maximum and minimum apparent temperature on respiratory drug sales in A Coruña from 2006 to 2010 were examined using a distributed lag non-linear model. In particular, low apparent temperatures proved to be associated with increased sales of respiratory drugs. The strongest consistent risk estimates were found for minimum apparent temperatures in respiratory drug sales with an increase of 33.4% (95% CI: 12.5-58.0%) when the temperature changed from 2.8 ºC to −1.4 ºC. These findings may serve to guide the planning of public health interventions in order to predict and manage the health effects of exposure to the thermal environment for lower degrees of morbidity. More precisely, significant increases in the use of measured OTC medication could be used to identify and anticipate influenza outbreaks due to a more sensitive degree of the data source.