Chiral drug synthesis and stereochemistry are critical in medicinal chemistry due to the distinct biological activities of enantiomers. Many drugs exist as chiral molecules, and often only one enantiomer exhibits the desired therapeutic effect. Stereo selective synthesis techniques, including asymmetric catalysis and chiral auxiliaries, are employed to produce specific enantiomers. The study of stereochemistry helps understand the interaction between chiral drugs and biological targets like enzymes and receptors. Regulatory agencies now emphasize the development of single-enantiomer drugs for improved safety and efficacy. Analytical techniques like chiral HPLC and circular dichroism assist in enantiomeric purity assessment. Advances in stereo selective synthesis reduce side effects and increase potency. Thus, stereochemistry plays a vital role in modern drug design and development.