Hi Debbie. My daughter is now 4 and just started school. She often bites her arm when she is angry or frustrated and has occasionally bitten other children. At first I was shocked and upset, now I just tell her to carry on as it is her arm she is hurting! When she realised that I was not reacting she seemed to do it less. She now only does it very occasionally. If another child is involved then she is put in time out and made to apologise. She is making progress, slowly but surely!