Generally speaking, thyroid cysts are benign lesions and are not dangerous. First, let's understand what thyroid cysts are. A thyroid cyst is a fluid-containing cystic formation found in the thyroid gland. Typically, the lump is round, smooth, painless, or may cause slight pain, and can move up and down with swallowing. Most cysts are solitary nodules, and it is less common to find multiple nodules. Additionally, if the cyst is large or if there is bleeding within the cyst, it can cause symptoms of compression such as pain, difficulty swallowing, difficulty breathing, and hoarseness. We know that about 10% of cystic nodules are malignant, hence, it is important to understand the nature of a thyroid cyst. If it is malignant, surgical removal is necessary. Furthermore, if the nodular cyst is large and causes compression symptoms, surgery is also required. However, most are benign lesions, and thyroid function is within the normal range, so no special treatment is needed, just follow-up observation. Therefore, whether thyroid cysts are dangerous depends on the circumstances.