The drug-to-carrier ratio has been a considerable issue in the design of a drug carrier, because the use of unreasonably high quantities of carrier can lead to problems associated with carrier toxicity, metabolism and elimination. However, if the carrier itself displays therapeutic effects, the drug-to-carrier ratio would no longer be a concern, and the delivery system should attain greater therapeutic effects from both the drug and the carrier. Epigallocatechin gallate (EGCG), a major ingredient of green tea, has been recognized as an attractive functional compound due to its various potential therapeutic effects, including anticancer effects. Herein we design the core-shell micellar nanocomplex (MNC) spontaneously constructed by self-assembly from the EGCG derivatives and proteins. This system achieved a greater anticancer effect in vitro and in vivo when loaded with an anticancer protein, as compared to the native protein or the carrier alone. This unique green tea-based MNC is the first nanoparticle drug delivery system that takes advantage of the beneficial bioactivities of EGCG.