It is OK to put Dry Ice into beverages for drinking as long as the dry ice is food grade.  Use 2 to 4 pounds of Dry Ice for each gallon of room temperature punch.

Use large pieces of Dry Ice not small pieces. The Dry Ice is heavier than ice and will sink to the bottom. Do not use any regular ice! The Dry Ice will do the cooling and must not be eaten or swallowed. Too much Dry Ice will freeze the beverage so have extra standing by.

It will bubble and give off the most fog when the beverage is room temperature. When most of the Dry Ice has sublimated, it will surround itself with ice and float to the top. There is still a small piece of Dry Ice in the center of these ice pieces so do not serve or eat them. Carefully ladle the beverage into drinking glasses without any Dry Ice. Add regular ice to glasses for cooler drinks.