AbstractFood by‐products happen at various stages of production and processing at home and on commercial scales. In the recent years, because of the fast‐growing food companies and production, food processing by‐products have gained a lot of interest and attracted many technical and health professionals as well as policy makers internally and internationally. Also, concerns are increasing about food by‐products due to their ecological and environmental impact on the planet. This is particularly of concern when large companies emit. Large quantities of food by‐products are thrown into environment in which they can be exploited technically, medicinally, and pharmaceutically. This is due to their chemical component and biologically active compounds of the by‐products. Therefore, this systematic review focuses on the food by‐product biological compounds present in different parts of the food products, particularly in some common foods such as fruits, vegetables, cereals, dairy products, meat, eggs, nuts, coffee, and tea. Moreover, the review also explains the kind of biologically active compounds and their quantity not just in edible foods, but also in part and types of the by‐product which then can be reused and recycled into different processes in order to extract and get benefit from.