When you or your child are diagnosed with an allergy, you probably walk our of the doctor’s office with a prescription for an allergy medication. When you have an allergy reaction, you’re instructed to take the medication to treat the reaction. What if instead of treating the reaction, we treat the source: the body’s reaction to the allergen. Sublingual Immunotherapy (SLIT) revolves around the idea that the body be trained not to be allergic to specific foods or substances.