All GI symptoms were significantly improved over time by Perilla frutescens extract during the intervention phase ( bloating : -@ , p = @ ; passage of gas : -@ , p = @ ; GI rumbling : -@ , p = @ ; feeling of fullness : -@ , p = @ ; abdominal discomfort : -@ , p = @ ) , whereas in the placebo group only abdominal discomfort was significantly improved ( -@ , p = @ ) .