Abstract: The present invention relates to improved methods for inhibiting aberrant cell proliferation involving the scheduling of administration of Chk1 activators (e.g., chemotherapeutic agents) and Chk1 inhibitors. At least one Chk1 activator is administered at a dose and for a time sufficient to induce substantial synchronization of cell cycle arrest in proliferating cells. Upon achieving substantial phase synchronization, at least one Chk1 inhibitor is administered to abrogate the cell cycle arrest and induce therapeutic cell death. The invention is useful with any Chk1 activator and any Chk1 inhibitor, and finds application in treating or preventing cancerous and non-cancerous aberrant cell proliferation.