Ralston Purina is being sued by a man who accuses the company of stealing his idea for a disposable cat litter box. Ralston-Purina is based in St. Louis. The lawsuit has been filed by a man from Edwardsville, Illinois who says he shared his idea with Ralston officials, then saw a Ralston product on the market a couple of months later that was almost identical to his idea. Sean McGivern wants more than 25-thousand dollars actual damages, with unspecified punitive damages added.