Of the 62 million common colds requiring medical attention in the United States each year, more than 80% affect school-aged children. Controlled clinical trials have demonstrated the effectiveness of zinc gluconate glycine lozenges (Cold-Eeze) in reducing cold duration. The objective of this study was to determine the effectiveness of zinc gluconate glycine lozenges in reducing the duration and severity of colds in school-aged subjects and to identify the benefits of prophylactic administration of zinc gluconate glycine lozenges in reducing the occurrence of colds. The medical charts of subjects enrolled at Utah's Heritage Center before and after the introduction of zinc gluconate glycine lozenges (between January 1998 and August 2001) were reviewed to identify those who experienced cold signs or symptoms. Two or more prespecified signs or symptoms on the same day identified a cold and, along with patient or medical staff reports and use of cold medications, were used to determine cold start and resolution dates. Results from subjects who did or did not take study treatment were compared statistically to determine the prophylactic effects of lozenge use. Effects of zinc gluconate glycine lozenges on the need for antibiotic therapy were also analyzed. The review encompassed 496 records. Treatment with zinc gluconate glycine lozenges significantly decreased cold duration (7.5 versus 9.0 days for nonuse; P < 0.0001). Prophylaxis also significantly reduced the median number of colds per year (0.0 versus 1.3; P < 0.001) and concomitant antibiotic use to manage colds (4.1% versus 36.2%; P < 0.0001). Therapy with zinc gluconate glycine lozenges significantly reduced cold duration and antibiotic use in school-aged subjects. Prophylactic administration also significantly decreased cold frequency.