The objective of this trial is to assess the clinical efficacy of a modified allergen extract of Olea europaea pollen in the treatment of patients affected by allergic rhinitis/rhinoconjunctivitis (with or without episodic asthma) induced by hypersensitivity to olea europaea pollen, evaluating the Score regarding Symptoms and consumption of the medication.

Immunotherapy is a specific treatment for allergic diseases. Unlike conventional pharmacological treatment, immunotherapy is the only treatment that could modify the natural course of allergic disease. This is a prospective double-blind placebo-controlled study with two arms of treatment: placebo and active.

Inclusion Criteria:

• Prior to study specific examinations the patient and if applicable both legal guardians has to give his/her written informed consent
• Patients of both gender aged from 18 and 55 years
• Patient's perception of disease activity of at least 30 mm on a 100 mm visual analogue scale (VAS)
• FEV1 greater or equal than 80% of the expected value, and if not, improvement of FEV1 greater than 12% after bronchodilation
• Patients have to suffer from allergic complaints (rhinitis and/or rhinoconjunctivitis with or without mild intermittent allergic asthma) caused by clinical sensitization against Olea europaea pollen. The IgE mediated sensitization has to be verified by:
• Suggestive medical history
• Specific IgE against Olea europaea pollen CAP RAST ≥0.7Ku/l
• Positive skin prick test (SPT) to grass Olea pollen resulting in a wheal diameter of at least 3 mm.

Exclusion Criteria

• History of significant clinical manifestations of allergy as a result of sensitization against weed pollen allergens and perennial (e.g. house dust mite.
• Participation in an immunotherapy with comparable extracts within the last five years.
• Treatment with β-blocker
• Any disease which prohibits the use of adrenaline (e.g. hyperthyroidism)
• Cardiovascular insufficiency or any severe or unstable pulmonary, or endocrine disease; clinically significant renal or hepatic disease or dysfunction; hematologic disorder; any other clinically significant medical condition that could increase the risk to the study participant
• Immunopathological diseases
• Patients who are expected to be non-compliant and/or not co-operative
• Women, where pregnancy is defined as the state of a female after conception and until the termination of gestation