Allergen immunotherapy is the only disease-modifying treatment for allergic diseases. Sublingual immunotherapy (SLIT) in liquid and tablet form has been used by clinicians in Europe for years, but has only recently gained popularity and approval in the United States. In 2014, the US Food and Drug Administration approved 3 SLIT tablets for the treatment of allergic rhinitis, with or without allergic conjunctivitis. Immunotherapy treatment strategies for the polysensitized patient vary between the United States and Europe. This variation hinges upon whether the polysensitized patient is truly polyallergic. Polysensitization is the positive response to 2 or more allergens on skin prick testing or in vitro specific-IgE testing. Polyallergy is the symptomatic clinical response to 2 or more allergens. In this review, we discuss the use of SLIT in the United States with a focus on treating the polyallergic patient with SLIT. (C) 2016 American Academy of Allergy, Asthma & Immunology (J Allergy Clin Immunol Pract 2017;5:41-5)