This study evaluates the use of various assessments of common cold symptoms for proof of efficacy of ColdZyme Mouth Spray on naturally acquired common colds. Half of the participants will receive ColdZyme® Mouth Spray while the other half may use optional care as needed.

Inclusion Criteria:

1. Men and women

2. Age 18 to 70 years old

3. Increased risk for common cold (at least 3 self-reported occurences of common cold within the last 12 months prior to V1) but generally in good health

4. Readiness to comply with trial procedures:

   • Use of IP as recommended (verum group)
   • Filling in diary
   • Keeping habitual diet and physical activity level

5. Women of child-bearing potential:

   • Have to agree to use appropriate contraception methods
   • Negative pregnancy testing (beta human chorionic gonadotropin test in urine) at V1

Participation is based upon written informed consent by the participant following written and oral information by the investigator regarding nature, purpose, consequences and possible risks of the clinical study.

Exclusion Criteria:

1. Known allergy or hypersensitivity to the components of the investigational product

2. History and/or presence of clinically significant condition/ disorder (self-reported), which per investigator's judgement could interfere with the results of the study or the safety of the subject, e.g.:

   • Nasal disorder (e.g. polyposis, relevant septal deviation, ulcer etc.) and/or reconstructive surgery
   • Acute/chronic airways disease/disorder (e.g. chronic obstructive lung disease, asthma, chronic cough of any origin)
   • Acute psychiatric disorders
   • Any other acute/chronic serious organ or systemic diseases

3. Influenza vaccination within the last 3 months prior to V1 and during the study

4. Regular use of products that may influence the study outcome (e.g. immune suppressants/immune stimulants including natural health products, analgesics/antirheumatics, anti-phlogistics, antitussives/expectorants, mouth or throat therapeutics, decongestants, antibiotics, anti-histaminergic drugs, nasal drops/spray) within the last 4 weeks prior to V1 and during the study (except for the defined optional care)

5. Pregnancy or nursing

6. History of (in the past 12 months prior to V1) or current abuse of drugs, alcohol or medication

7. Participation in the present study of a person living in the same household as the subject

8. Inability to comply with study requirements according to investigator's judgement

9. Participation in another clinical study in the 30 days prior to V1 and during the study

Individual participant data that underlie the results reported, after deidentification (text, tables, figures and appendices) will be shared with researchers who provide a methodologically sound proposal, to achieve aims in hte approved proposal.

Beginning 3 months and ending 5 years following article publication.

Individual participant data that underlie the results reported, after deidentification (text, tables, figures and appendices) will be shared with researchers who provide a methodologically sound proposal, to achieve aims in hte approved proposal. Proposals should be directed to fredrik.lindberg@enzymatica.com. To gain access, data requestors will need to signa data access agreement.