Prostate cancer (PC) is one of the leading cause of cancer related deaths in men. PC progression and recurrence following initial treatments possesses mortality threat amongst these patients. Cell cycle re-entry of quiescent cancer cells has been suggested for cancer progression and recurrence. The slow progression of PC allows a window of opportunity for intervention through diet. An inverse association of flavonoids intake and PC development has been demonstrated in epidemiological studies. We hypothesized that citrus peel that is rich in various bioactive compounds including flavonoids may impede cell cycle re-entry by quiescent PC cells.