A "probiotic study caused a furor in the Netherlands in 2008, when the adverse outcome—24 deaths in the probiotics group (16%) and 9 deaths (6%) in the control group—was announced at a press conference 23 January, 3 weeks prior to publication in The Lancet."

In "Report Slams Deadly Dutch Probiotic Study," the author, Hans van Maanen would have required a medical-ethical committee study the effects of probiotics on animals and healthy volunteers before allowing its general use in humans. Indeed, contrary to the authors' assertion in their Lancet article, the study was not done according to Good Clinical Practice (GCP).