Dr, i have a black furry tongue, is it transferable to my girlfriend. i have good oral hygiene, don't smoke, don't use any un prescribed drugs?

Not transferable: This is not transferable to your girlfriend. Here is a site where you can learn more about black hairy tongue, causes and treatments. http://www.mayoclinic.org/diseases-conditions/black-hairy-tongue/basics/definition/con-20034518

Good news: Not transferable. Often seen in association with antibiotic therapy. A Dentist can help you with management.