The main purpose of medical petroleum jelly is to moisturize the skin. Most of this substance can generally be used as a base for other types of topical ointments, so it has a wide range of applications. On the one hand, it can be used as a mechanism for medication, and on the other hand, it can be used directly on the skin. It is especially effective for some dry skin diseases, such as pruritus or ichthyosis, etc. It also has obvious therapeutic effect for some chronic eczema, especially dry eczema. In addition, it also has a certain moisturizing and protective effect for some chronic diseases that cause skin chaps, cracks, as well as hypertrophy and hyperplasia. It is also useful in preventing infection in cases where the skin is already traumatized and has some cracks. So the role and use of Vaseline is very wide.