What's the most natural treatment for anxiety disorders?

Anxiety. The most natural treatment is exercise. Free, and extremely effective. Just 20 minutes of brisk walking a day will do it. Meditation or just taking time out for sitting in silence, 10-20 minutes a day, will also help a lot. Many people find certain teas and warmed milk helpful.
Meditation. Meditation, please see your primary provider if this condition doesn't improve.