The objective of this trial is to assess the clinical efficacy of the modified extract (depigmented and polymerised with glutaraldehyde)of the subcutaneous injection of Phleum pratense pollen in the treatment of patients affected by allergic rhinitis/ rhinoconjunctivitis ( with or without episodic asthma) induced by hypersensitivity to grass 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 in an up-dosing cluster regimen for 4 weeks.

Inclusion Criteria:

• Informed consent, signed by the subject.
• Clinical History of moderate to severe rhinitis/rhinoconjunctivitis lasting for at least 2 consecutive years, with or without episodic asthma, caused by allergy to grass pollen.
• Patient of both gender aged from 18 up to 55
• Symptoms that coincide with allergy to grass pollen
• Sensitivity to grass pollen, diagnosed through a positive skin reaction to Phleum pratense: Positive prick test and /or Specific IgE to P.pratense >0,7KU/L Patients included must be mono-sensitised or, in the case of poly-sensitisation, sensitivity to p.pratense pollen should be considered as the only relevant aspect of their condition from the clinical standpoint.
• Patients who are able to comply with the dose regime

Exclusion Criteria:

• Patient with mild Rhinitis/rhinoconjunctivitis
• Relevant sensitivity to another perennial allergen
• Use of immunotherapy during the last four years
• Treatment with B. Blocking agents
• Patient suffering from some pathology in which adrenalin was contraindicated
• Subject suffers from a serious medical condition, which would interference the treatment and follow up of the subject in the study
• Subject suffers from autoimmune disease(thyroiditis, lupus, etc.)
• Conditions in which the patient can not offer full co-operation and significant psychiatric disorders.
• Intolerance to aspirin
• Pregnant women or with pregnancy risk and breast-feeding