Yes you can put plants in your bathroom as long as the plants are suited for the bathroom because of the high humidity that bathrooms have.
I have a spider plant and a Fern in my bathroom which are good plants for bathrooms that love the humidity that a bathroom has.
You can also put other plants such as Bamboo, Boston Fern, Aloe Vera, Peace Lily, Cast Iron Plant, Orchard and the Snake Plant.
Those are some good plants that are good to keep in bathrooms.