Unexplained crying occurs in about 1 in 5 infants. The crying starts 2 to 4 weeks after the due date and occurs between 6 p.m. and midnight, for about 3 hours a day. It is manifested by hard-to-soothe crying, leg extension or stirring, abdominal bulging and exhaustion. When not crying, the child is well fed and in good spirits. The cause of this crying is unknown (called colic Colic). Parents need not be alarmed. It usually gradually decreases and stops by 3 months of age. The first episode may require the doctor to rule out conditions such as intussusception or hernia. The cause of this colic is still unknown. One of the following methods may be effective. 1. Breastfeed the child, and the mother does not eat irritating foods such as dairy products, peppers, coffee or onions. For infants with crying caused by food allergies, colic stops after 1 to 2 days. 2.Hold the baby walking and gently rocking to help him fall asleep through rhythmic movements and body contact, but avoid shaking the baby vigorously to avoid brain damage. 3.Wrap the child in a blanket to make him feel warm and safe. 4.Put the child’s abdomen on the knee joint and then gently rub his back, the pressure on the abdomen helps to relieve the pain. 5.If the how method does not stop the crying, you can let the baby cry for a while and fall asleep automatically.