The antioxidative capacity of phytochemical compounds is often discussed in life science courses (to prevent or slow cancer) and food science courses (to prevent the oxidation of sensitive ingredients). Thus, we developed a laboratory experiment where the photochemical reaction of lightsticks is used to qualitatively demonstrate the antioxidative capacity of compounds such as ascorbic acid (vitamin C) or flavonoids. The experiment can be used as an instructor demonstration or performed by students. It is low cost, quick to perform, and reliable in practice. (Contains 1 table, 2 schemes and 1 figure.)