Locally administered levamisole and copper levamisole enhanced leucocyte migration into inert sponges implanted into rats for either 4 or 48 h. The stimulated cell was the polymorphonuclear neutrophil. Penicillamine and its copper complex were ineffective. However, all four compounds were effective in enhancing leucocyte migration into sponges implanted into arthritic rats when the drugs were incorporated into the sponges before implantation. Their overall antirheumatic actions may thus have common elements.