Melatonin is a hormone secreted into the bloodstream by the pineal gland and is primarily known to promote sleep and regulate sleep cycles and wakefulness. In general, melatonin is taken in small amounts and intermittently by patients and usually does not cause major damage to the organism. If melatonin is taken for a long time, it can produce certain side effects, such as gastrointestinal reactions, fatness, sleep rhythm disorders, hangover phenomenon, frequent nightmares, memory loss, increased prolactin release, allergic reactions, stroke, poor mental health, withdrawal reactions, etc. 1, gastrointestinal reactions: patients may experience abdominal pain, bloating, diarrhea, constipation, etc.; 2, fatness: melatonin contains certain hormonal components, if Patients often take melatonin, may lead to fat, and it is difficult to lose weight; 3, sleep rhythm disorders: long-term use of melatonin will not only lead to treatment of insomnia worse, but will lead to sleep rhythm disorders aggravated, in the long run can lead to neurasthenia; 4, hangover phenomenon: most of the sleeping pills can lead to the phenomenon of hangover, waking up after the performance of dizziness, head swelling, concentration; 5, nightmares Frequent: some patients taking melatonin, may have nightmares, so that the quality of sleep is reduced; 6, memory loss: long-term use of melatonin, may lead to memory loss, in the long run may develop into Alzheimer’s disease; 7, increased release of prolactin: melatonin can increase the release of prolactin, and the increase in the release of prolactin in the body, can lead to patients with decreased libido, menstrual disorders, amenorrhea The increased release of prolactin in the body can lead to decreased libido, menstrual disorders, amenorrhea, lactation and other symptoms, and can even affect the function of fertility; 8, allergic reactions: patients allergic to melatonin may develop rashes, itchy skin, red throat, etc.; 9, stroke: melatonin can promote the contraction of blood vessels in the brain, increasing the risk of stroke; 10, poor mental health: long-term large amounts of melatonin, easily lead to depression, manifested as mental depression, fatigue weakness, slower reaction, etc.; 11, withdrawal reactions: long-term use of melatonin can make patients dependent, when the drug is discontinued may appear a series of withdrawal reactions, such as headache, dizziness, nausea, vomiting, tremors, and even convulsions and other manifestations. Melatonin is generally secreted at night from 23:00 to 3:00 am to reach a peak. If melatonin levels are insufficient, insomnia and early awakening are likely to occur, and melatonin secretion is generally rhythmic. If melatonin is used to treat insomnia, moderate control of diet, proper exercise, and increased exercise during the day are recommended to help rest at night and avoid relying on melatonin for sleep.