Babies are especially anxious if they have diarrhea, because once they have diarrhea, they are especially prone to dehydration, which is classified as mild, moderate or severe according to the severity of the dehydration. Once a baby shows signs of dehydration, he or she may show a strong desire to drink water. In mild dehydration, the baby’s fluid loss accounts for less than 5% of body weight, the baby is slightly worse in spirit, slightly pale, the skin is slightly dry but still elastic, the eye sockets are slightly sunken, the fontanelle is not obviously sunken, and the urine is slightly less than usual. In infants with moderate dehydration, the loss of body fluid accounts for 5% to 10% of body weight, the child is depressed and irritable, the skin is pale and gray, dry, flaccid, with poor elasticity, the abdomen is sunken, the fontanelle is slightly sunken, the limbs are cold, the baby’s tears decrease significantly when crying, and the urine is significantly reduced. In severe dehydration, the baby loses 10% to 15% of its body weight in fluids, is depressed, indifferent, pale and gray, has very poor elasticity, blood pressure is not easily measured, the abdomen is deeply sunken, the fontanelle is also significantly sunken, the extremities are cold, the baby cries without tears, and urinates very little or no urine. Dehydration in infants must be actively corrected, otherwise severe dehydration may endanger the life of the infant, so it must be given sufficient attention.