Tryptophan belongs to the essential amino acids, as a drug is common as an injection, mainly used for niacin deficiency, but also has the effect of regulating mental rhythm and improving sleep. Tryptophan can constitute 5-hydroxytryptamine neurotransmitter, is one of the essential amino acids, commonly used as injections, can be used to treat niacin deficiency, also known as pellagra, can be used as special nutritional supplements for pregnant women and infants, but also has the effect of tranquilizing the mind, regulating mental rhythms, and improving sleep. Tryptophan as a drug adverse reactions and contraindications are not clear, should be used under the guidance of a doctor, follow the doctor’s instructions to take medication, daily attention to develop good habits, pay attention to balanced nutrition, less spicy and stimulating food, pay attention to rest, work and rest.