Perhaps the best-researched herb for overall liver health, milk thistle contains a group of antioxidant compounds commonly called silymarin, which bind to liver cells and prevent harmful chemicals from breaching cell walls. Silymarin also promotes cell regeneration and boosts levels of glutathione, a critical antioxidant that zaps harmful free radicals produced when liver enzymes break down toxins. A 2010 study of 50 children undergoing chemotherapy found that those who took oral milk thistle for 30 days had significantly less liver toxicity than the control group. Dose: 100–200 mg daily of milk thistle bound to phosphatidylcholine for better absorption.