A method for separation and determination of sorbic acid, a food and beverage preservative, and trans-resveratrol, a biomedically active substance, in wine by capillary zone electrophoresis is described. A solid-phase extraction step on C18-column prior to the electrophoretic separation providing lower detection limits was used for transresveratrol determination. For determination of sorbic acid direct analysis of wine (without a preconcentration step) was used. The method is rapid and sensitive and was applied to the analysis of wines from Alsace, France.