How do I react to growling or biting?

What does NILIF stand for?

NILIF = nothing in life is free

One thing you can do is step back and say a command that you are sure he will respond to. It is a non-aggressive way of calmly enforcing obedience.   
 
ETA: You might want to check out this thread: [linkhttp://forum.dog.com/asp/tm.asp?m=97960]http://forum.dog.com/asp/tm.asp?m=97960[/link]

ORIGINAL: Birth32
I know now that he is the alpha dog and we are working on that by using something similar to NILIF. I love this guy with all my heart and am willing to do anything. Any word of wisdom would be great. Thanks.

Seeking help from a behaviorist is a great idea, as is NILIF, but be careful of thinking of your dog as "alpha".  I prefer to think of a controlling dog as a "wannabe" or an "opportunist".  It keeps you thinking of how to outsmart your wannabe CEO, rather than how to dominate him.  The most important thing is to convince him, simply and kindly, that you are in charge of the household.
One thing I have found useful is to have my clients hand feed their dogs for about two weeks, and to withhold any toys, treats, etc.  That way, ALL resources come from you - and that makes you into a leader pretty quickly.  Also, it really isn't necessary to go out doors before him, but it does help to ask him to "sit" or "lie down" before he is able to go through the door.  No manipulation or force is necessary, because if he doesn't sit, you just walk away.  Come back in a few moments and try again.  You are simply making him "ask permission", and when he is compliant, you will let him out.  Leaders have opposable thumbs LOL. 

In what situations does he bite or growl? How have you been reacting to him so far?

He bit me a few weeks ago when I was drying off his paws. I yelled (I know thats not the thing to do now) and he growled at me and then ran downstairs and hid behind a chair. Then just this past weekend my wifes friend, who is a regular and he knows very well, was sitting spread eagle on the floor with him belly up between her legs getting belly rubs and he just snapped. Luckly he didn't actually bite her but it wasn't for a lack of trying. I ran downstairs to see him chasing her into the bathroom. When he saw me he ran behind the same chair and when I came over and he was growling. We've never been aggressive with him so I'm really confused with his behavior recently. Thank you all for your help.
 

OK, Sam and I just got in from our normal evening run. When we got back I tried to make him sit. He was being stubborn as usual so I tried to help him by pushing lightly on his butt until is head reared back really fast and the growled at me. I told him No and told him to sit again and he just ran downstairs and is now hiding behind the chair again. He'll sit if he knows he's getting a treat but I wasn't about to give him a treat after that.

If this is a new behavior, a trip to the vet wouldn't hurt.

We were just there yesterday and he is in good shape physically. He got two shots in the butt. This behavior started about 2-3 months ago. 

I'm sure many will disagree with me, but I would say if that's typical of the situations in which your dog growls at you, he's a dog for whom corrections and physical manipulation don't work. Try clicker training or other hands-off PR methods instead. Are there any other situations in which he growls or bites? When you say bite is he breaking the skin, bruising, or just putting pressure on the skin?

Not to be the only freak here, but I have a disabled dog who knows he's disabled (as much as a dog can) and he's more concerned than my other dog about space, about having enough, and about having enough to escape crazy/busy situations, and about having enough space and time to get away and to look and make sure nobody is "touching" his sore spots.
 
He has HD and not every vet can diagnose this. I'm not saying Sam does, of course, but I am saying that maybe looking into things a bit more medically will give you more to work with and consider.
 
After writing to this group and after talking to my vet and a behaviorist, I have a decent game plan that is WORKING! Yes, it's working, slowly but surely.
 
I realize, too, that Murphy is VERY sore, all the time, and while I am working to fix that the best I can, I have a few things I need to keep in mind (making sure he has enough space to move/hobble around in).
 
Given that this is just starting up (unless you missed earlier signs of this starting up), please also pursue medical issues, too.

He was being stubborn as usual so I tried to help him by pushing lightly on his butt

 
Would you rather be asked to sit, or would you like me to push you into a chair?  It may be that your dog is in pain somewhere (maybe he does have HD), and reluctant to sit, or it may be that you are not perceived as a leader, or that he isn't as confirmed in his commands as you think he is (some dogs know the body gestures you make when you want them to sit, but they really don't know the word "sit" very well).  Either way, it seems that you need to re-create your relationship with this dog.  I agree with jones.  Try clicker training him and keep your hands off.
You could start by hand feeding him for a couple of weeks and avoid extraneous treats - so he will see you as the provider of resources.  Also, avoid staring, leaning over him, and any physical correction or manipulation.  If you want a trainer to coach you on clicker techniques, you can find one at [linkhttp://www.clickertraining.com]www.clickertraining.com[/link].  And, if you want to see some videos of a clicker trained dog, go to [linkhttp://www.clickertrainusa.com]www.clickertrainusa.com[/link].  The trainer in the video is a member here (Gal Ziv).

Thanks for pointing that out something very important about touching dogs when training,  Spiritdogs. I don't really like touching my dogs when training with them, either. And should a dog have a medical/pain issue, it's even more important to remember.
 
Your signature is so true--dogs automatically go against force and pressure, so getting them to "sign up and into" the training exercises is not only easier on everyone, but you see results more quickly.
 
Thanks, too, for helping me with Murphy. No kids around him (or in my house) for now, and nobody is allowed near him, though he is becoming quite curious and less fearful with my "controlled" visits. It's been very positive and I'm feeling more confident in myself, too.
 
 

You all make some good points. Maybe clicker training will help, I'm willing to try anything. We meet with the behaviorist tomorrow at 5:30 pm. I'll keep you posted. Thanks again....