After your son has calmed down, apply Step 1 of the 2X-Rule (see Raise Your Kids without Raising Your Voice for a detailed explanation of the 2X-Rule). Tell him that it's O.K. to be mad. It is not O.K. to slam doors. The next time he slams a door, apply Step 2 of the 2X-Rule. Tell him again that anger is acceptable, slamming doors is not. Let him know that from now on, door slamming will result in a negative consequence (tell him exactly what consequence will occur). On the third time he slams a door, give him the consequence. Use the same consequence 3 or 4 times to see if it is affecting the door slamming behavior. If it isn't change the consequence and continue until you find "the right priced ticked."  Sarah Chana