IntroductionRespiratory allergies to grass pollens are very widespread in the general population and the treatment is generally symptomatic which sometimes remains insufficient. Grass pollen allergen immunotherapy is currently the only etiological treatment of seasonal allergic rhinitis apart from allergenic eviction. AimThe aim was to study the effectiveness of sublingual ITA tablets with 5-grasses on allergic disease and describe the adverse effects after one year of treatment. MethodsWe conducted a prospective, descriptive and evaluative study including 40 patients suffering from grass pollen allergic rhinitis. A grass pollen sublingual allergen immunotherapy was received and patients were followed during a one-year treatment to study the efficacy and the safety profile. ResultsThe mean age was 30.9±12.25 years. The sex ratio (M/F) was 0.48. Allergic conjunctivitis was associated in 70% and allergic asthma was associated in 48% of cases. Allergen immunotherapy side effects were mild, consisting of local side effects. No severe side effects were observed. A decrease in allergic rhinitis symptoms was observed in 83% with improvement in medication score in 65%. All patients noted a decrease in conjunctivitis symptoms with a total regression in 54% of cases. A better asthma control was noted in 33%. Among the 19 patients suffering from asthma, we could decrease the drug use in 63% of cases during the first year of treatment. An improvement of the quality of life was observed in 78% of cases. Allergen immunotherapy was significantly more efficient in allergic rhinitis and conjunctivitis with patients under 30years old. ConclusionGrass pollen allergen immunotherapy leads safely to the regression of allergy symptoms and improves the therapeutic load and the quality of life.