10-yr Golden seems to have stomach issues

Question
My 10 yr old female golden has been having bouts of diarrhea.  No fever or other signs of illness shown.  The food hasn't changed. Feeding only in morning, Purina 1 for well over a year now.  No table foods have been given.  Could she have developed a food allergy?

Answer
Could be a lot of things.  Try this for a week:

If a dog is having trouble keeping anything down or continuing diarrhea try this out of the manual I have from a large, knowledgeable dog guide school.

Bland recovery diet for dogs.

3 parts cooked rice, one part boiled hamburger or chicken, or cottage cheese. I think you can substitute boiled potatoes for the rice. Once in an emergency, we bought a plain baked potato from Wendy's.

This is meant for short time settling a dog's digestive tract. It is not the complete and balanced diet they need long term. I have seen it work.

If she firms up, slowly switch to the Purina 1  It is a fine chow.  Don't let the food snobs tell you otherwise.  

If not, better check with the vet.