The baby’s recent temper tantrums and crying may be caused by the parents, lack of vitamin D, respiratory tract infections and other reasons. 1. Parents: If the parents are grumpy, the baby will be insecure, like to cry, but also imitate the parents, appear grumpy appearance. 2. lack of vitamin D: may be the baby’s physical development is relatively fast, will lead to a lack of vitamin D in the body, caused by increased nerve excitability, so that the baby appeared to be crying, grumpy, sweaty and other symptoms. 3. Respiratory tract infections: generally caused by viral infections, the baby will have sore throat, fever, chills and other symptoms of the disease, causing the baby’s physical discomfort, resulting in the baby’s love of crying and grumpy phenomenon. When the baby has such symptoms, parents should promptly give the baby to regulate, so as not to affect the health of the body.