Mo. Rev. Stat. § 510.150: Effect of dismissals, with and without prejudice.

A dismissal without prejudice permits the party to bring another action for the same cause, unless the action is otherwise barred. A dismissal with prejudice operates as an adjudication upon the merits. Any voluntary dismissal other than one which the party is entitled to take without prejudice, and any involuntary dismissal other than one for lack of jurisdiction or for improper venue shall be with prejudice unless the court in its order for dismissal shall otherwise specify.