Recent studies on the kinetics of the regeneration reactions of vitamin E in solutions by means of stopped-flow spectroscopy confirmed that the quantum effect often plays an important role. Vitamin E may inhibit the autooxidation of lipids in cellular membranes by taking advantage of proton tunneling. It is interesting that the microscopic quantum-mechanical tunneling effect manifests itself in a macroscopic vital function. Although this finding is in conflict with our intuition at first glance, living cells might, in reality, know quantum mechanics very well and use them effectively.