Introduction of new concept may promote science development. In recent years, the concept of redundancy has gradually infiltrated into life science. Functional redundancy of cytokines and transcriptional factors has attracted much attention. However, cellular redundancy remains ill-characterized yet. Recent development in study of adult stem cell plasticity and professional and amateur phagocytes arouse exploration of cellular redundancy. Relevant information concerning cellular redundancy and antiredundancy are summarized, the function and significance of cellular redundancy are discussed from the angle of biomedicine, and active investigation in cellular redundancy is suggested.