There are general causes for many behavior problems:  lack of physical and/or mental exercise, isolating your dog for extended periods of time, boredom, and loneliness. 

There are general solutions for behavior problems, all of which are important:  provide your dog with more and appropriate physical and mental exercise, the right kind of play, and, especially, the right kind of training.

First, make sure your dog does not have a physical problem, i.e., toothache,  stomach problem, or nutritional imbalance. Puppies chew to help with the pain of teething.  Give them ice cubes for relief.

If he chews when you are not home, he may have some separation problems and you need to exercise him more, a lot more, and work on building up his confidence with basic obedience exercises so he can stay alone for extended periods.

Punishment for chewing does not work because it is generally done when you come home and your dog does not associate the chewed items with your unhappiness.  Teach him what are appropriate chew toys and praise him when he chews on the right toys so that he will chew those toys when you are away.  

These are only partial solutions.  Learn how to show him acceptable behavior in a way that makes sense to him so you are both working together for a common goal.

Please have patience.  Habits do not change overnight.  Give yourself and your dog a chance. 

Article submitted by Caryl Wolff, www.DoggieManners.com