Introduction: Research shows that individuals consume more calories when provided with a larger portion size. It is unclear if similar behavior translates to topical medication use. The impact of container size and provider instructions on patient usage of topical medications has yet to be assessed. Methods: Data was collected from 128 participants in an IRB randomized, controlled trial. To a marked 3cmx8cm rectangle on the forearm, patients applied petroleum jelly from either a large container or a small tube. Pre and post application container weights were measured. Results: Patients applied more topical medication from the large container compared to the small tube. Conclusion: Topical medication usage is influenced by the size of the container provided. It is beneficial to consider container size when prescribing topical medications and greater application is desired.