I believe some sort of botulism which can lead to unnecessary death. Not sending this to scare you but honey is definatly not good for the little one. Talk to your pediatrician he will have alternatives if constipation is a problem. I agree with Brigitte, honey is not good for your young one. Please check with your doctor.
Doctors are rather strict about that here in Sweden.
So take it easy and try the apple and prune juice.