The Maillard reaction is a non-enzymatic reaction between reducing sugars and amino acids or proteins that leads to browning and formation of carbon dioxide and aroma. This reaction can be divided into three stages. The early and intermediate stages products have been studied in detail, while the late or advanced stage products are wide variety of low- to high-molecular-weight compounds and not fully understood. These products are essential for determining the palatability, quality, and safety of food. In human body, the Maillard reaction progress gradually leading to the deterioration of protein function, making it important in physiology and pathology. The late-stage reaction products produced in the body are called AGEs (advanced glycation end products). To evaluate the impact of the Maillard reaction in both food science and human health, it is necessary to identify each of these diverse compounds and to clarify the reaction conditions and reaction pathways.