Alternative routes for immunotherapy have been explored, especially in Europe in an attempt to improve patient compliance and to minimize the risk of serious adverse reactions. For example, sublingual-oral immunotherapy (SLIT), which is the administration of the allergenic extract/vaccine under the tongue for 1-2 minutes followed by swallowing, has been proven to be efficacious and safe in several double-blind, placebo-controlled studies. A recent Cochrane Review concluded, "SLIT is a safe treatment, which significantly reduces symptoms and medication requirements in allergic rhinitis."