Sublingual immunotherapy (SLIT) has been used mainly in European countries and Latin America, and more recently in the United States. SLIT has been increasingly used due to its high safety profile and the convenience of home application. Droplet application is the most commonly used method in the world. In the United States and Europe SLIT can also be performed with dissolvable tablets. Allergic patients apply the vaccine sublingually every day or on specific days of the week. Adverse reactions are infrequent, and when they occur are generally mild, with symptoms commonly associated with the patient's allergic disease.