Immunostaining for metallothionein was performed on olfactory mucosa of the superior part of the nasal septum obtained from Alzheimer's disease (AD) patients and normal age-matched controls. In general, specimens from AD patients showed increased MT immunoreactivity as indicated by more frequent and intense staining in Bowman's glands, olfactory epithelium and the underlying lamina propria. Induction of MT may result from increased levels of reactive oxygen species commonly associated with AD. Sections of the entire nasal cavity and olfactory bulb of apoE-deficient and wildtype mice revealed no difference in the pattern of staining, suggesting that MT expression is not linked to the apoE gene.