Out of control 3 year old

I am a mother of three children my two older children are great but my three year old son is so out of control that I do not know what to do. He throws stuff and breaks things if he gets mad, hits me and every disipline I try he just laughs at me and goes right back to what he was breaking. Also he will not potty train and thinks it is really funny when he uses the potty in his pants please help.

[margypops]

How does he get on with your older children, are they kind to him or does he get teased at all, what happens prior to him throwing things,and hitting, does anyone else in the family hit ,he could be copying.Make sure it is him and he is not antagonised and use the time out method, sit him on a chair till he is good and make him stay there.,do not react ,do it  simply and quietly.Take off diapers and pullups as they enable the wetting and get him some big boy pants and lots of praise when he uses the potty, tell him before that he is a big boy now and he doesnt need diapers and pullups they are for the Babies.you may get some accidents to start with just clean up.He will be okay first check out what is the cause of his behavior.