The pentose phosphate pathway (PPP), also known as the hexose monophosphate shunt, is an alternative glucose metabolism pathway to glycolysis. It generates NADPH and pentoses through oxidative and non-oxidative phases. NADPH is important for biosynthesis of fatty acids and antioxidation, while pentoses such as ribose-5-phosphate are precursors for nucleic acid synthesis. Certain tissues like liver and red blood cells heavily utilize the PPP. A deficiency in glucose-6-phosphate dehydrogenase, the first enzyme in the oxidative phase, can cause hemolytic anemia upon exposure to oxidative drugs or foods.