The toxic potential of three major components of soft contact lenses was assessed in white mice. Accepted procedures for toxicological studies were used to evaluate the effects of 2-hydroxyethyl methacrylate, ethylene glycol, and methacrylic acid. No observable signs of gross toxicity were detected in any of the mice injected with the original doses. Larger doses of methacrylic acid produced ataxia, irregular breathing, convulsions, and death. From the concentrations of these chemicals normally occurring in contact lenses, no systemic toxic effects would be expected.