Pharmacogenetics, the study of interindividual variations in DNA sequence related to drug response, aims at the optimization of treatment regimens based on each patient's unique genetic makeup. Currently, there is a trend towards moving away from the concept of "one drug fits all" to a rather more individualized and personalized medicine. The goal is to define the appropriate drug dose that maximizes efficacy and minimizes toxicity in each individual patient. An example of genotyping for CYP2C9 genetic polymorphisms in patients receiving oral anticoagulants is provided. In spite of its inherent challenges, we hope that pharmacogenetic research and clinical applications expand to improve healthcare outcomes in Lebanon and worldwide.