Interproximal wire-telemetric plaque pH data were obtained from five volunteers after they ate milk chocolate bars, raisins, chocolate wafer cookies with cream filling, cupcakes with icing and cream filling, and cherry pies. All the foods produced rapid decreases in plaque pH for extended periods. In a second set of test sessions, volunteers chewed sugarless gum for 10 minutes, starting 15 minutes after they ate the snack food. In all cases, the gum chewing caused a rapid increase in plaque pH. The pH remained at a level considered safe for teeth for 30 minutes after chewing the gum.