Recently, the development of selective and powerful inhibitors for enzymes and receptors by structural basis chemical biology is desired. The development has been made successfully by addition of potential to form covalent-linkage with the target-protein to affinity component. Michael acceptors are a powerful and hopeful function to introduce a potential of the covalent-linkage formation to the anticancer agents. This short review describes several recent examples utilizing the covalent-linkage based on the Michael addition reaction in vivo and a possibility of reversible control of the adduct formation.