Patient description: A 39-year-old man came to the clinic with cough and shortness of breath that was not relieved by his inhaler. He had these symptoms for 5 days during the past 2 weeks. He doubled his oral corticosteroids in the past week. He is a chef with a history of asthma for 3 years, suffering from frequent cough, wheezing, and shortness of breath and chest tightness. The symptoms become more bothersome within 1-2 hours of starting work every day and worsen throughout the work week. His symptoms improve within 1-2 hours outside the workplace. Spirometry was performed revealing a forced expiratory volume in the first second (FEV1) of 63% of the predicted. His past medical history is significant for seasonal allergic rhinitis in the summer. He doesn't smoke or use illicit drugs. His family history is significant for asthma in his father and sister. He currently uses inhaled corticosteroid (ICS) and fluticasone 500 mcg/salmeterol 50 mcg, one puff twice daily.

Clinical trial eligibility criteria: eligible ages (years): 18.0-60.0,  Rhinitis Male and female subjects Aged 18 to 60 years People with nasal and ocular discomfort at least sensitized to grass pollen Subject with PER allergy (persistent form) as defined by ARIA guidelines or with a recurrent history of seasonal allergic rhinitis documented by treatment intakes in his medical dossier Previous positive skin prick test or presence of specific serum IgE antibodies class II or above against timothy grass in the last 5 years. If no data are available, a test for detection of timothy grass specific serum IgE antibodies (Phadia CAP System) will be performed at the pre-inclusion visit With RQLQ score ≥ 2 Subjects agree to stop consumption of probiotics (food or dietary supplement containing probiotics) and vitamins and/or minerals during the study (D-10/D-7 to D49). Female subjects with efficient contraception and asthmatic subjects (with a controlled disease and without oral corticosteroid) can be included in the study. The baseline period prior to treatment with Lactobacillus paracasei LP-33 is 7 days. On recommendations of the consulted experts, Pr Bousquet and Pr Hamelmann, a wash-out period of 3 additional days is recommended before baseline for subject using intranasal corticosteroid before their inclusion. As a consequence, the baseline may be extended to 10 days for these subjects In case the subject consumed an anti-H1 (other than Loratadine) before his (her) he (she) will have to switch to Loratadine to be included  Taking part in another clinical trial or being in the period of a previous clinical trial Presenting a psychological incapability or having a bad comprehension of the language (French or German according to the concerned country) to understand the information letter and then to sign the informed consent Refusing to sign the informed consent Adult under legal protection (guardianship, wardship) or deprived from his rights following administrative or judicial decision Pregnant or breastfeeding women Use of medication which could interfere with the study in the investigator's opinion (antibiotics, etc…) Subject who does not agree to stop his/her consumption of dietary supplements and foods containing probiotics and his/her supplementation of vitamins/minerals during the study (D-10/D-7 to D49)