Flowers have been used for healing in virtually all countries and cultures.
In the wild, animals seek out plants that will improve their health or just make them feel good. A dog eating grass is a common example.
I saw my dearest poodle Monona enjoying peppermint leaves in our garden many times.
When we domesticate animals we remove them from their natural environment and so from many of the natural foods and remedies which they would seek out for themselves.