What can I give him to calm him down.

Chasing people is fun and dogs like to win and the people always go away when he chases them so he always wins. For him its a fun game with no repercussions.
One thing you can do is whenever he tries to chase someone turn around and go the other way from the direction he wants to go in.
You may feel and look a little silly for a bit but eventually he will figure out that the chase game is no longer fun.
Even an older dog can benefit from training and a trainer might be near you that can help a lot too - if the dog is busy walking at heel and keeping you in view so he can see what you might want next that will earn him a reward chasing won't be as much fun as doing what he is told is - check www.apdt.com for a trainer near you.
Hope this helps you!

Edited by NHolmes on June 29 2005 at 4:19pm

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This doesn't seem to be a play type activity. He seems intent on attacking these people. It is not something he has ever done before these past few weeks. He was always afraid of people and would want me to pick him up when people came near.
He has always been a very well behaved dog and did have training and until recently would stop what he was doing and come when I called his name..he now ignores me and takes off. He was a product of a puppy mill and was seen at Tufts by Dr Dodman regarding all his fears several years ago.

I understand it seems serious to you and that the dog may be serious about it but if you view it as a game its easier to handle.
Somehow he recently learned he can 'win' at this and scare people and run off and have fun doing it.
Training isn't a one time thing you have to keep it up often for life.
As he was a puppymill dog he may have spent all this time with you building up his confidence and now he is believing he really can 'run the world' and be 'in charge' if he wants to.
You stated he is on a leash so I don't understand how he can run down the street after people and ignore you.
You might find the behavior changes you see will calm back down if you try the nothing in life is free program with him. You can read about that here www.ddfl.org/behavior/nilif.htm and that should help put you back in the role of leader that seems to have somehow slipped away recently.
Its not something a pill can cure. If you worked with Dr Dodman then you know that meds are only a means to assist training and not the resolution of the problem.
You can of course have him checked by a vet for a health problem. If this is something that just started up a health issue might be triggering him to 'attack first' before the strangers get too close.
I'd work with him on leash too and remind him coming when you call is a good thing and earns him rewards which are much nicer than having his owner chase him and be upset.

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