Only a few studies analyzed the pharmacoeconomics of allergen immunotherapy compared with drug treatment in subjects with allergic rhinitis and asthma. This study was aimed at evaluating whether allergen immunotherapy has an economic advantage on standard antiallergic drugs in patients with pollen-induced rhinitis and asthma. Thirty patients with rhinitis and asthma caused by Parietaria pollen were included in the study, 20 (11 men and 9 women; mean age, 35.45 +/- 10.45 years) were treated with subcutaneous immunotherapy by a Parietaria judaica extract (Alustal, Stallergénes, Antony, France) by a conventional build-up schedule in 12 weeks and a maintenance treatment every 4 weeks for 3 years, and 10 (6 men and 4 women; mean age, 31.90 +/- 10.97 years) were treated with antiallergic drugs. Each patient was evaluated before starting the treatment and annually for 6 years in the pollen period of Parietaria by means of nose, eyes, and lung symptom scores, along with drug consumption registered in diary cards. In other specifically designated cards general practitioner's or specialist's visits, the number of desensitizing injections and the number of boxes of antiallergic drugs were registered. A significant difference in favor of immunotherapy plus drug treatment versus drug treatment alone was observed, reaching a cost reduction of approximately 15% the second year and 48% the third year, with a highly statistical significance that was maintained up to the sixth year, i.e., 3 years after stopping immunotherapy, when an 80% reduction was found. The net saving for each patient at the final evaluation corresponded to euros 623 (dollars 830)/year. These findings confirm some previous observations in studies from Germany and the United States that subcutaneous immunotherapy has significant economic advantages over antiallergic drug treatment in the long term.