Since the discovery of human serum paraoxonase (PO N1), the enzyme has been the subject of various fields of
research. Initially, PO N1 was identified as an enzyme
capable of hydrolysing organophosphate compounds, but
there is a growing body of evidence that PO N1 plays a role in lipid metabolism and the onset of cardiovascular disease. Still, the precise mechanism by which PO N1 functions <i>in vivo</i> remains to be clarified. Here we will briefly review developments in the field of PO N1 research which merit further attention.