Abstract
After treatment with diphenylhydantoin for 2 yr because of postinfarct focal motor epileptic seizures, a 35 yr old woman was admitted to hospital because of intoxication symptoms. Almost every sign of the previous left-sided paresis and hypesthesia had disappeared. A pronounced gingival hyperplasia was found almost exclusively in the left side. The concentration of immunoglobulin[Ig]A in serum was far below normal. Admitting that she had not been careful brushing her teeth in the left side because of the strange feeling there (dysesthesia), the patient had actually carried out a controlled trial proving that she, being predisposed to gingival hyperplasia with a low level of IgA in serum, could almost prevent the gingival hyperplasia in the right side by brushing her teeth carefully.