Sebaceous cysts are a type of benign proliferation with various onset factors. The most common factor is the vigorous secretion of one's own sebaceous glands. If the local subcutaneous excretion is not smooth, it gradually accumulates over time to form a cyst. Some people develop the cyst because of a local purulent infection, leading to folliculitis or an abscess. Over time, if the pus is not completely eliminated, it gradually dries and accumulates to form a tofu-dregs-like substance. Once this disease is detected, common medications can no longer remove it. One can visit the dermatology department of a standard hospital to have a minor surgery that completely removes the cyst and the tofu-dregs-like substance. Maintaining good dietary and lifestyle habits can help suppress the recurrence of this condition.