Covalent drugs have shown success in treating various diseases but have been largely avoided due to safety concerns. This review discusses the resurgence of covalent drugs in drug discovery, highlighting their pharmacological advantages and the potential risks that can be mitigated through innovative design. Covalent drugs form irreversible bonds with their targets, offering high potency and selectivity. Despite initial reluctance, covalent drugs have been approved for many clinical indications and have made a significant impact on human health. Examples include clopidogrel, esomeprazole, and proton pump inhibitors, which have achieved blockbuster status. The review also discusses the prevalence of covalent drugs, their mechanisms of action, and the challenges in their development. Covalent inhibitors are designed to target specific non-catalytic residues, offering distinct selectivity profiles compared to reversible inhibitors. The review emphasizes the importance of structure-based drug design in optimizing covalent inhibitors and highlights the potential of covalent drugs in treating diseases such as cancer and infectious diseases. The review also addresses the safety concerns associated with covalent drugs, noting that while they can cause adverse reactions, recent advances in analytical techniques have improved the understanding of their mechanisms and safety profiles. The review concludes that covalent drugs offer a promising approach for drug discovery, with the potential to address many challenges in the development of new therapeutics.Covalent drugs have shown success in treating various diseases but have been largely avoided due to safety concerns. This review discusses the resurgence of covalent drugs in drug discovery, highlighting their pharmacological advantages and the potential risks that can be mitigated through innovative design. Covalent drugs form irreversible bonds with their targets, offering high potency and selectivity. Despite initial reluctance, covalent drugs have been approved for many clinical indications and have made a significant impact on human health. Examples include clopidogrel, esomeprazole, and proton pump inhibitors, which have achieved blockbuster status. The review also discusses the prevalence of covalent drugs, their mechanisms of action, and the challenges in their development. Covalent inhibitors are designed to target specific non-catalytic residues, offering distinct selectivity profiles compared to reversible inhibitors. The review emphasizes the importance of structure-based drug design in optimizing covalent inhibitors and highlights the potential of covalent drugs in treating diseases such as cancer and infectious diseases. The review also addresses the safety concerns associated with covalent drugs, noting that while they can cause adverse reactions, recent advances in analytical techniques have improved the understanding of their mechanisms and safety profiles. The review concludes that covalent drugs offer a promising approach for drug discovery, with the potential to address many challenges in the development of new therapeutics.