Provided herein are methods, compositions and formulations to prevent or ameliorate ethanol intolerance, reduce or ameliorate symptoms associated with acetaldehyde accumulation accompanying ethanol consumption, or reduce the risk of diseases or disorders caused by acetaldehyde accumulation, comprising administering 4-MP, or physiologically acceptable salts thereof, to subjects with reduced or absent aldehyde dehydrogenase subtype 2 (ALDH2) activity.