Objective: The aim of our study was to examine immunoreactivity between AβP-42, toxic chemicals, and food proteins that could be involved in AD. Methods: We applied monoclonal anti-AβP-42 to a variety of chemicals bound to human serum albumin (HSA) and 208 different food extracts. Results: We found that anti-AβP-42 reacts from moderately to strongly with mercury-HSA, dinitrophenyl-HSA (DNP-HSA), phthalate-HSA, and aluminum-HSA, but not to many other tested chemicals bound to HSA nor to HSA alone. This antibody also reacted with 19 out of the 208 food antigens used in the assay. One example of a food that reacted strongly with anti-AβP-42 in our study was canned tuna, although raw tuna reacted only moderately. Conclusion: Based on these results, we hypothesized that reaction between AβP-42 antibody with chemicals bound to HSA and numerous food antigens might play a role in Alzheimer’s disease (AD). These anti-AβP antibodies could be derived from protein misfolding similar to β-amyloid, or from antibodies to various food antigens that cross-react with AβP-42. Removal of toxic chemicals and food items that share a homology with β-amyloid may be recommended at least for patients in the early stages of AD. Therefore, the role of AβP-42 cross-reactive foods and chemicals bound to HSA in neurodegeneration should be investigated further.