Artificial liver support is a therapeutic option for subjects with fulminant hepatic failure. Results of these studies suggest a possible favourable effect on this condition. The aim of the present review is to evaluate not the results of the different artificial systems available but the methodology used to achieve these results. A computer and manual search of the literature was performed; 832 pertinent references were retrieved. Seventy-seven were full papers reporting the application of artificial liver support in animals or humans (15 RCTs (3 in humans, 12 in animals), 53 uncontrolled phase I trials, 9 case reports). The results of this review indicate that, although the rationale of artificial liver support as shown by animal studies is acceptable, the widespread use in clinical practice is not justified and a controlled design for the studies on artificial liver support systems is mandatory.