Baby picking at his mouth while crying, may be because there are mouth ulcers, may also be teething, but also does not rule out the starvation situation, need to be targeted according to the specific circumstances of the treatment.1, mouth ulcers: baby malnutrition, lack of vitamins, dry weather and other reasons, may cause abnormal changes in the oral cavity, induced mouth ulcers. After the baby appeared mouth ulcers, the mouth will be uncomfortable, so will pick at the mouth while crying. At this time should be timely to pacify the baby, you can use watermelon cream under the guidance of the doctor for treatment; 2, teething: baby in teething, the gums will be swollen, itchy and other discomforts, can also appear while picking at the mouth while crying. You can use gauze dipped in saline to gently wipe the gum area, and you can use your fingers to gently massage the gums to relieve the baby’s discomfort; 3, hunger: babies are generally fluids-based food, the frequency of hunger is relatively fast. When the baby appears hungry, may also pick at the mouth while crying, at this time should be fed to alleviate the symptoms.