Most canines have an aversion to red pepper flakes, and they work well to keep dogs out of flowerbeds and gardens. The red pepper flakes have the same effect on dogs as they do on people. They cause a lot of sneezing and watery eyes, but dogs have a keen sense of smell, and they'll avoid the area altogether. -- I found this info and I have shared it with my mother-in-law as well. I hope this might prove fruitful for you.