My Lhasa Apso has Inflammatory Bowel Disease and I started this product a few weeks back. She had a flare-up a few days after beginning the vitamins and at this time, I'm not sure if the vitamins were the cause or not. She is on a home cooked diet, due to her inability to tolerate most commercial dog food, so I felt she needed some supplemental vitamins. At this time, I've taken her off the vitamins until her intestinal tract settles back down and plan to try the vitamins again within a few days. Therefore, I'm unable to rate the vitamins at this time.