Benefit and Tolerability of IQP-AS-105 in Reducing Susceptibility to Upper Respiratory Tract Infections

Inclusion Criteria: * age 18-70 years * increased risk for infections - at least 4 cold episodes within 12 months * commitment to adhere to their accustomed diet and physical activity * women of child-bearing potential have to agree to use appropriate birth control methods * written consent of the subject to participate is a prerequisite for study participation Exclusion Criteria: * acute / chronic upper airways disease * chronic cough of any origin * acute / chronic lower airways disease * any allergic reaction that may influence the study outcome (e.g. acute/chronic rhinitis) * history of nasal reconstructive surgery * presence of nasal ulcers or nasal polyps * severe nasal septum deviation or other condition that could cause nasal obstruction * congenital or acquired immunodeficiency disease (e.g. HIV infection) * severe organ or systemic diseases * body temperature above 37.5°C * suspected swine flu or influenza * vaccination against influenza or swine flu within 3 months prior to study start * stomach/gastrointestinal diseases * sleep disorder * psychiatric disorders * known sensitivity to the ingredients of the investigational product * intake of products that may influence the study outcome within the last 14 days prior to study start and during the study * analgesics , antibiotics or decongestant nose drops/spray, unless they are used as rescue medications * pregnancy or nursing * alcohol / drug abuse * simultaneous participation in another clinical trial or participation in a clinical trial within the last 30 days * insufficient compliance