Currently available animal and human liver models provide limited predictions of human drug efficacy and toxicity, primarily due to metabolic differences and the limited ability of simple 2-D models to recapitulate the complex cellular interactions that lead to toxicity. To fill this gap we have developed a novel 4 cell type, 3-D, microfluidic, human liver model with the ability to monitor multiple cellular toxicity and human disease related functions over at least 28 days.