Drug metabolizing enzymes (DMEs) play a major role in the metabolism and final elimination of most drugs and xenobiotics from the body. Both phase I and phase II enzymes are highly polymorphic. Most studies on the pharmacogenetics (PGx) of DMEs and its influence on interindividual variability have been conducted in Western countries. Middle Easterners, however, may have a different genetic makeup and may be exposed to different environmental factors when compared with their Western counterparts. Thus, results obtained in Western populations cannot be extrapolated to the population of the Middle East, and it is important to examine and document PGx differences and influences within the Middle Eastern population as there have been very little published data from this region. Herein, we provide an update on the genetic polymorphisms of DMEs that were studied in Lebanon and their impact on drug toxicity and efficacy. It is hoped that with more time, additional funds, and perseverance, the PGx of DMEs in Lebanon picks up and becomes closer in quantity and quality to that in the West.