I am going to say no because Miralax is a drug and it contains chemicals which are harsh, expecially for an infant. Have you read and tried natural ways of relieving constipation? Have you changed the diet or figured out what the cause of the constipation is? Drugs are a last resort and only after you have really, really, tried everything else. My daughter was chronically constipated last year when she was one. Guess what? It was my fault. Obviously I was doing something wrong and I needed to figure out what. After a month of her being constipated and hurting everyday I figured out that because it was hot out, she needed more water, less milk and yogurt for starters. Once I figured that out it went away and she hasn't been constipated since. Try having the child drink apple juice......hope this helps.