Diarrhea

My 7 year old male Boxer/Lab/Golden Retriever has been battling diarrhea since 02/09/25. He went to the vet and lab work was good so diagnosed with viral infection or stress. We went bland diet of chicken, rice and prescription wet dog food plus antibiotics for 10 days. At 10 days his stools were almost normal. 3 days after the antibiotics were done diarrhea returned with some streaks of blood in it. The vet put him back on antibiotics and 5 days of prescription wet dog food and continued bland diet. His antibiotics ended last Thursday however his stools were like soft ice cream and now diarrhea has returned again today and is like water. He has been on probiotics since this started. He had lab work done at the first visit and it was all normal. He acts fine, has a good appetite just diarrhea. He has been very on this bland diet since 02/10/25. Any ideas of what could be causing this or what else I should have him tested for? I am open to any thoughts or suggestions. Thanks

Hello and thank you for this topical question.  I'm not sure where in the world you are or whether there is part of the history I am not familiar with, but in the UK these days antibiotics are rarely considered a first-line treatment for large-bowel diarrhoea in an otherwise healthy pet..   Furthermore, antibiotics do not tend to be used to treat gasterointestinal viral infections (antibiotics usually target bacteria rather than viruses).  The history caused me to wonder whether the drugs are indeed antibiotics, or whether perhaps your vet knows something extra about this case that I have not grasped.  I also wonder whether the antibiotics are indeed what is solving the problem - might it be the chicken and rice that is helping?  Chicken and rice sounds in your account to be different from the prescription dog-food; has this food been prescribed for diarrhoea or for something else?  If prescribed for the diarrhoea, it doesnt sound as though it is working;  I do not understand the need to try chicken and rice first?  Might there be a different prescription dog food, perhaps one based on chicken and rice, that you might try?   What, for example, would happen if you tried or extended the chicken and rice diet without antibiotics?  These are idle musings;   I do not know enough about your dogs' case to suggest  treatments, not least because I have never met them or seen the history.  Rather, these are questions to put to your vet.  For example, "How do we know that the antibiotics are working here?  Whst do you think would happen if we tried the chicken and rice without antibiotics?" Another good question could be whether allergies or a mild reaction to something in that particular precription dog-food could be involved? Regarding testing, it is diffcult to carry out a faecal test for an allergy.  I wonder whether or not your vet feels that parasitic egg-counts might be useful?