Ethanol and acetaldehyde levels in blood and urine have been evaluated in 9 volunteers following administration of Liv.52 and placebo on the evening of the study and on the following morning. On the following morning the volunteers scored their symptoms and completed visual analogue scales. Single dose and multiple dose studies were done. Liv.52 produced a considerable reduction in blood and urine levels of ethanol and acetaldehyde after 12 h. It is possible that Liv.52 prevents the binding of acetaldehyde, bringing about higher initial blood levels followed by rapid elimination. It reduced the hangover symptoms.