This study is divided into two parts. In part 1, 60 patients with histology-confirmed NASH will be randomized to receive Hepaguard or placebo for 24 weeks to test the efficacy. Endpoints will be assessed at week 24. The aim of part 2 is to test the durability of Hepaguard. Forty patients originally on Hepaguard will be randomized again to continue Hepaguard for another 24 weeks or stop the treatment. The endpoints at week 48 will be further analyzed.