Aromatherapy along with hydrotherapy do not work recent research say. Vitamin C is not effective either, according to these studies. No matter how much you laugh, pray, avoid caffeine in your food and drink or keep to a carbohydrate-rich/protein-poor diet, or how many hours a week you spend on yoga. This measures are absolutely uneffective in anxiety disorder treatment.
But if you swap praying for meditation, and yoga classes for dance/movement therapy together with music, you increase the chance that your effort will be paid off. In the same category you can find relaxation therapy, exercise, bibliotherapy, autogenic therapy, massage (might be effective for kids only, researchers say), inositol and acupuncture.
Some treatments, such as kava and 5-hydroxyl-L-tryptophan, are effective but kava brings with it severe side effect, such as liver toxity and 5-hydroxyl-L-tryptophan can cause eosinophilia-myalgia syndrome.
The conclusion investigators came to is that the majority of complementary and alternative medicines so popular nowadays cannot be accepted as an adequate alternative for treating anxiety disorders.
You can read more at herbal alternative medicine articles.