When an allergen enters the body, the immune system kicks in to counter to the effects. In most cases, the immune systems produce histamine, which causes the symptoms typically associated with allergies and hay fever: headaches, sneezing, watery or itchy eyes, nasal congestion, and scratchy throat. Allergic substances range from pollens to environmental and chemical pollutants. Smoking can also contribute to nasal congestion. To treat allergies, most people need to reduce exposure to the allergen and take medication, often antihistamines and nasal decongestants. For more severe cases, immune therapy is utilized to stimulate resistance allergens which are causing patients their symptoms. Immune therapy involves administering a serum to the body which contains dissolved allergens. In the past administration has been done through injections into the arms. In our practice, the serum is introduced under the tongue, known as sublingual immunotherapy. We treat both children and adults and have been employing this method since 2001.