According to Healthline, zinc lozenges, such as Cold-EEZE, may help treat the symptoms of colds but are ineffective in preventing colds. The evidence on the use of zinc lozenges for colds is, in general, mixed and inconclusive.
According to the manufacturer, Cold-EEZE lozenges contain zinc gluconate. Healthline says that while the evidence on effectiveness is inconclusive, the evidence on side effects from zinc lozenges is not. In small doses, zinc lozenges can cause a metallic taste in the mouth, nausea, vomiting and diarrhea. Heavy use of the lozenges can cause stomach pain, coughing and fatigue. The zinc can also interfere with the mechanism of other medications.