GS with diaherra

Question
My 8 yr old, male, non neutered, just got his distemper vac. yesterday and now has diaherra.  Is this common?

Answer
No it isn't common.  Maybe my dogs have had over 100 shots and never any kind of a reaction.  I would call the vet.  Likely you will be told to withhold food for 24 hours.  You may also be told to put it on a bland diet until it firms up.  One advantage of alerting the vet is it will go into his records and next time the vet may select something else.