Oral hyposensitization was carried out in 26 patients with pollinosis and in 67 patients sensitive to house dust with all year symptoms of allergic disease of the skin, airways or conjunctivitis. The patients were hyposensitized with grass pollen extracts and house dust produced by Lab. Sevac. The pollen allergen was administered before the pollinating season, in increasing doses during 18 weeks. The following concentrations were used: 0.1 PNU, 1.0 PNU, 10 PNU, 100 PNU, and 1000 PNU. The house dust allergen was administered in the same manner, using the same concentrations and time during autumn and winter. In the group of patients with plant pollinosis 10 out of 26 did not experience any symptoms of the disease after hyposensitization. In 9 further patients the symptoms were milder. In the group of 44 patients with atopic dermatitis sensitive to house dust, a complete cure was seen in 62% of the patients. In further 25% milder symptoms were observed. In the group of 11 patients allergic to house dust and with the asthma-prurigo syndrome, the respiratory and dermatologic symptoms resolved completely or diminished in 3 and 6 patients respectively. In the group of 7 patients with dermatitis and full year rhinitis, complete resolvement of symptoms was seen in 2 patients and diminished symptoms in 3 cases. In the group of 4 patients with conjunctivitis full resolvement of symptoms was observed in 3, while partial in 1. Only in 3 out of 93 treated subjects intolerance of this therapy was found.(ABSTRACT TRUNCATED AT 250 WORDS)