In order evaluate the long-term benefit of Specific ImmunoTherapy (SIT), administered either subcutaneously or sublingually, in comparison with drug therapy, in terms of efficacy, tolerability and patients' adherence to the treatment, a three year perspective, observational study was carried out over tree years in a rather large number of allergic subjects. One hundred and ten patients of both sex (50F, 60M; age: 22.4 - 35.5 years) were admitted. Sixty of them were rhinitics, some with concomitant mild intermittent asthma or conjunctivitis; 43 had a persistent asthma, often with concomitant rhinitis. Seven had urticaria. Sixty patients were treated with the allergoid sublingual SIT (in tablets) plus drugs on demand, 19 with the subcutaneous SIT (depot, aluminium hydroxide subcutaneous SIT) and 31 with the pharmacological therapy alone, mainly nasal steroids and antihistamines. The treatment efficacy, evaluated after 36 months, by symptoms and drug consumption reduction, was statistically better in the group assigned to the allergoid sublingual SIT than in the other two groups. This was the case also for the tolerability, the patient's compliance and the physicians' and patients' opinion. The present findings, obtained by a non-randomized study, show that the allergoid sublingual SIT was very appreciated by both patients and physicians for the good effectiveness and the high degree of safety guaranteed, in addition to its simplicity of use.