The effects of formaldehyde and glutaraldehyde alone and in combination with sucrose on antigens reactive with pemphigus antibodies, bullous pemphigoid and antinuclear antibodies were studied. All antigens were rendered non-reactive to their corresponding antibodies after single treatment with formaldehyde or glutaraldehyde. However, the antigenicity of at least some antigens combining with antinuclear antibodies could be restored with 30% sucrose solution. On the other hand, the antigens for pemphigus or bullous pemphigoid antibodies could not be recovered by the sucrose treatment.