Drug induced liver injury is an uncommon but important and challenging form of liver disease. When evaluating a patient with new-onset liver disease, drugs, including prescription medications, over-the-counter preparations, vitamins, dietary supplements and herbals, must always be considered as a possible cause. Indeed, the possibility must be entertained even if another cause may seem obvious, such as hepatitis B or C. The reason for this is that drug induced liver injury can be severe and even fatal, but is usually reversed by discontinuation of the offending agent. To continue a medication in the face of drug induced liver injury can have serious consequences. Drug induced liver injury is a growing challenge because of the ever increasing number of drugs used in medical care and the increasing number of individuals who take them. Among the thousands of drugs available today, several hundred have been linked to liver injury, but the clinical pattern of liver injury is diverse and can mimic almost any form of liver disease. Drug induced liver injury can present in a pattern that is similar to acute hepatitis, chronic hepatitis, acute liver failure, biliary obstruction, or fatty liver disease. To keep track of which drugs cause liver injury and what pattern is typical of each agent is challenging to even the most dedicated subspecialist in the area. Furthermore, the literature on drug induced liver injury is large and dispersed to publications in many disciplines ? pharmacology, internal medicine, hepatology, gastroenterology, pediatrics, and surgery. Publications on drug induced liver disease often appear as short reports or letters to the editor that are difficult to access, including many that appear in foreign language journals that may not be available in local medical libraries. As a result, it is difficult to keep abreast of the literature and literature searches on specific medications are often incomplete. While there are several excellent textbooks on drug induced liver disease, they may be difficult to obtain and are rapidly out of date as new medications are introduced and more literature appears.