Adverse drug reactions are a major health risk that contributes to increasing health care costs and strain on the system. They are the sixth leading cause of death in the United States, and statistics indicate that the situation would be similar in Canada. There are many types of adverse drug reactions. Liver toxicity (poisoning) leading to fatal liver failure is one of the most common. In most cases, the mechanisms that cause drug induced liver toxicity are not well-known and even less is known about the effects of natural products (herbal products or dietary supplements) on liver function. With the ever increasing demand of herbal products by consumers, there is an urgent need to conduct detailed and systematic scientific investigations on their hepatic metabolic effects. Dr. Chang’s work is aimed at characterizing the effect of natural products and synthetic drugs on liver function and determining how they are able to give rise to damage in liver cells. A better understanding of the mechanisms will contribute to a safer and more rational use of natural/herbal products and synthetic drugs.