Elderberry, a great antiviral scientifically proven to be effective against the influenza virus, has been used for centuries to help fight off colds, flu and other respiratory illnesses. (1)

Licorice root has well-documented antiviral, antibacterial and antifungal properties. Many studies have shown it to be effective and it tastes good too. (2)

Olive leaf is another plant with well documented antiviral properties and has been scientifically proven to shorten the durations of upper respiratory infections. (3)

Vitamin C won’t cure your cold but can it help you get over it faster if you take it daily as a preventive measure. (4)

Monolaurin a component of coconut oil, is a proven antimicrobial most effective against lipid membrane bacteria and viruses. (5)

1.   https://www.researchgate.net/publication/259696401_An_Evidence-Based_Systematic_Review_of_Elderberry_and_Elderflower_Sambucus_nigra_by_the_Natural_Standard_Research_Collaboration

https://www.ncbi.nlm.nih.gov/pubmed/9395631

2.   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629407/

https://www.thieme-connect.de/products/ejournals/abstract/10.1055/s-0033-1352073

3.   https://www.researchgate.net/publication/272168441_Olive_Leaf_Extract_OLE_exhibits_antiviral_activity_against_H5N1_Avian_Influenza_virus http://www.altmedrev.com/archive/publications/14/1/62.pdf
4.   https://www.ncbi.nlm.nih.gov/pubmed/19263912

https://lpi.oregonstate.edu/mic/vitamins/vitamin-C

5.   https://pdfs.semanticscholar.org/ae11/39046d35bf42deccbfd7d1a6757388a6d8b7.pdf

https://www.liebertpub.com/doi/abs/10.1089/act.2006.12.310