I had that problem with DD 1 and when I talked to the nurse she asked me what brand I was using (S-26), and she advised me to try another brand as sometimes some kids get constipated with S-26. I changed to Karicare and haven't looked back, started DD2 on it straight away when she started bottle feeding. Also the nurse said when I wanted to use the Inner Health Plus for kids to get a teaspoon turn it around and only use the amount that would fit on the end of the teaspoon handle for each bottle (mind you, not those big round handles just the normal slim ones!).