Ferroptosis is a new type of cell death mechanism induced by iron-dependent lipid peroxidation occurring in cell membranes. While lipid peroxidation has been studied extensively over many years, research on ferroptosis is progressing rapidly as a potential target for the prevention and treatment of various diseases. Approximately 50 years ago, I began my academic career by researching lipid peroxidation through gas chromatography-mass spectrometric analysis, focusing on oxidative rancidity in food chemistry. I expanded my research into the pathophysiological function of lipid peroxidation products and the role of dietary antioxidants such as flavonoids and carotenoids in lipid peroxidation in vivo. My research on lipid peroxidation was discontinued due to my retirement from Tokushima University in 2016. In this chapter, I examine my research on lipid peroxidation and acknowledge the recent increasing prominence of ferroptosis. I hope my research over the past year has advanced the study of lipid peroxidation and ferroptosis in academia.