What Are The Side Effects Of Cremaffin Syrup In Child?

hi,my son is 3yr old.I m giving cremaffin syrup for his constipation problem as suggested by my pediatrician .iwould like to know whether this syrup has got any side effects since i have been giving this syrup for my kid for more than 2yeard .if i dont give the syrup for his its very difficlut to pass.he passed hard stool sometimes with blood .pl advise me