I would give him the plain white rice, maybe half a cup or so to start mixed with a little chicken broth. Wait a few hours and see how he does. If the diarrhea persists a trip to the vet may be in order.
Did he eat anything different or possibly get into the trash or something? Often it will clear up on the rice and broth if it is just something they ate.
Just read about the possible mouse. That would definitely cause an upset system, but no permanent damage. However mice may carry parasites, so you may want to take a stool sample to your vet later to have it checked for worms. Just to be on the safe side since you are not sure. In any case try the rice and if the diarrhea calms down keep him on the rice and chicken diet for 24 hours until his system settles down.
Did he eat anything different or possibly get into the trash or something? Often it will clear up on the rice and broth if it is just something they ate.
Just read about the possible mouse. That would definitely cause an upset system, but no permanent damage. However mice may carry parasites, so you may want to take a stool sample to your vet later to have it checked for worms. Just to be on the safe side since you are not sure. In any case try the rice and if the diarrhea calms down keep him on the rice and chicken diet for 24 hours until his system settles down.