Nope it possiblly is not harmful, unless she has any kidney infection. But is it necessary? Morarji Desai used to drink doesnot mean everyone should.
But I heard before cow urine has some good effect.
Cow, what an animal. Almost each and every part of this animal is useful in this way or that way. From meat, skin, horn, bones, milk, dung and even urine, God created this animal with all good things. No wonder its so special, throughout the world.