We have a St. Bernard/boxer who is 4-1/2-yrs. old.  He is male and neutered.  He bit my sister when he was about 1-yr-old, and then two other people.  One my daughter-in-law in her own house.  He made puncture wounds on bother arms. 

Needless to say, we only have family members coming in house and two young grandchildren who he loves.  When we walk him he is good and doesn't bother with anyone, unless they would put their hand on us someway.  Same with auto, if someone comes too close to car he growls and will bite I think.

We love this dog but it is very hard not to have company because obviously we're afraid of what he will do.

I'm sure someone else must have this problem.  Would like to hear from someone on this is possible.

 Thank you

Joan S.