We recommend NuVet Plus!
It has especially done wonders for my 13 year old Shepherd Mix. His digestive system has been off for the last couple of years. Despite probiotics and food changes, this problem remained. After 6 weeks on NuVet Plus, there was major improvement and now, his system is totally back to normal.
For more in depth info, click on the NuVet Labs tab at the left of the page.