 A long-time career goal for him was to elaborate methods to determine human hepatotoxicity (and particularly cholestasis-inducing abilities in drugs) from animal tests; although this endeavour was never a success, it led to a much improved understanding of the mechanisms of cholestasis.According to Plaa, much of his mechanisms- and protocols-oriented research was an effect of his original formation in criminalistics.Plaa's scientific career led to the publication of 233 peer-reviewed articles bearing his name, as well as 48 book chapters and literature reviews.