There is probably no person in the world who would have positive associations with the wors sebum. Its excess is expressed by unsightly skin shining – do you know it? Unfortunately, I do. Sebum is produced by sebaceous glands located on the whole surface of the skin except the inner side of the hands and feet. Some parts of the skin are equipped with a larger number of glands than others, so the sebum is not secreted evenly over the entire body surface. Where is the largest amount of sebaceous glands located and what are their types? Is sebum needed and what affects its quantity? What are the effects of excessive sebum secretion? How does the secretion of sebum affect the type of skin and how to reduce it?