Is it harmful to eat glass, sand and microplastics? On the one hand, silicon dioxide can also cause physical damage to human organs. Because of the high density of silica particles, it can be adsorbed and deposited on the surface of digestive tract for a long time, which leads to the decrease of digestion ability and has the ability to form stone nuclei. Before 2008, many researchers thought that animals could excrete any particles they ingested, such as what they called "unnatural fibers". However, the biological experiment of eco-toxicologist mark brown proves that this is not the case. The smallest silica particles, like microplastics, can enter the blood, lymphatic system and even the liver, causing inflammation and thrombosis. For details, please refer to microplastics's related literature on physical injury to human body. The difference between silicon dioxide particles and microplastics is that silicon dioxide does not produce chemical toxins, but the physical harm to human body is the same in theory. The standard of any additive has always been to choose between the two, and to choose the lesser of the two evils. With the progress of science, the disadvantages of some so-called safety additives will gradually emerge and be eliminated in the long river of history.