Sebaceous glands are small glands that are located in the skin and produce an oily substance called sebum. There are several synonyms for sebaceous glands such as oil glands, sebum glands, and pilosebaceous glands. These glands are found throughout the body except for the palms and soles of the feet. They are usually connected to hair follicles and play an important role in keeping the skin moist and lubricated. Overactive sebaceous glands can result in oily skin and acne, while underactive glands can cause dry skin and hair. Maintaining the health of sebaceous glands is important for overall skin health.