my Labrador has been given tramadol after major surgery to remove a mast cell tumour from her head. She went to an Oncology referral practice, and was an in-patient for 2 days following her surgery. We have to give her one 50mg tab twice daily. She has now devoloped diarrhea. Could this be the cause. I cannot seem to find this has been a problem for any other dog. She is still having half of a steriod (predniserone) tablet every other day. This is to gradually wean her off them.She had taken them for almost 3 weeks prior to her surgery. When we first got her home she would not eat, I cooked her chicken and gave it to her with rice. Her diarrhea was absolutely full of undigested rice. Surely this could not have caused it, or could it be that simple? Her appetite is fine now, and I stopped the rice this morning. (28th Feb.2015)