Hello Mrs
First of all, you should give your child plenty to drink and encourage him/her to consume fibers such as sweet potatoes, fruits, vegetables, oat cereals, etc. This is the best way to soften the stool.
You should encourage your child to drink a lot, I suggest increasing the frequency of drinking, every 2 to 3 hours, even if it means giving smaller quantities at a time.
I also suggest that you give her exercises when she is on her back, such as squatting (making her knees touch her chest) and cycling.
For constipation, PEG-3350 (LAX-A-DAY, Restoralax and other brands) can be given as a tasteless, odorless powder to be diluted in a small amount of any drinkable liquid. The amount of powder is given according to your child's weight, 1 gram of powder per kg of your child's weight. Your pharmacist will be able to show you how to measure the exact dose, as only the adult dose is indicated on the package.
I hope this has been helpful to you and if you have any further questions, please do not hesitate to ask!
Tom Samaha, Pharmacist