Dogs need grass to munch on just like cats do. They eat it to settle their stomachs and get some fiber to help keep things moving along. Clover is a medicinal plant and I would not worry about him/her eating this. What I would do is to keep an eye on her/him because the grass/clover eating could be a sign that there may be digestive disturbances. However, this is probably just the normal meal of greens that dogs enjoy occasionally.