Here is a photo of a service flag labeled Medical Corps. I'm still looking for the back story behind this artifact. It came from the Elvis John Brassfield family, though I'm not sure who was in the medical corps and which war they served in.
If you should see one of these flags with a blue star hanging in a window, it means that household has a family member in harm's way. A gold star signifies that a family member died in service to the country.