Background: ColdZyme is a medical device and is the product that is mainly recommended for a cold at a pharmacy. ColdZyme prevents or shortens a cold by the cod trypsin Penzyme to form a protective barrier in the throat so that viruses cannot attach and spread further. Aim: To compile clinical studies to evaluate ColdZyme’s clinical effect on a common cold’s time course. Methods: Literature search was performed in the databases PubMed, Cochrane, Medline and Google Scholar with a quantitative approach where selected studies were reviewed with CONSORT questionnaire. Factors regarding internal- and external validity were analyzed in order to be able to assess the evidence value of the studies. Findings: Five studies were included with varying designs where two studies were considered to have low quality and three studies moderate quality according to CONSORT. The evidence value was considered low for all studies except for a randomized controlled trial with high evidence value. The data were summarized in tables and text and showed a proven clinical effect of ColdZyme, a common cold time course decreased with varying number of days when using ColdZyme. Conclusion: The studies resulted in fewer cold days when using ColdZyme. Since there was only one randomized, controlled study and a limited number of studies with poor quality and evidence value, the conclusion about a proven clinical effect is not reliable.