Although there are many reports on methanol and formaldehyde intoxication, none pays attention to the protein misfolding that is potentially involved in the pathological way, in particular the effect of formaldehyde on protein polymerization.Damage of neuronal cells caused by misfolded protein aggregates is one of the most significant problems in both neurology and pathology.Tau is a major microtubule-binding protein that is important for the assembly and stabilization of microtubules.Misfolding of tau is related to a pathological way of neurodegeneration.