My 7 year old dog took to munching on his own feces. The first time he did it I called my Vet who sold me 5 days worth (5 packets) of this medication for $20.50. It worked for a few months but then the disgusting behavior began again. This time I purchased it through Amazon. I bought 12 packets for $21.99. Now that’s a much better deal for the exact same product. So we did 5 days again, the behavior stopped and I have extra in case it returns. Yuck!!!