Self-Help Tips From Dr Sarah Brewer

Nature’s Answer To Respiratory Infections

Flavonoids – the antioxidants that protect plants from viral infections – can now help to protect us from colds and ‘flu, too. These flavonoids are present in Cold & Flu Guard™ which, when sprayed into your mouth and nose, remains as a thin layer for up to three hours to trap unwanted viruses and bacteria. The patented natural active ingredient, known as Flavobac™, then envelops the trapped viruses and bacteria and inactivates them – just as they do to protect plants – so they can no longer reproduce or cause harm.

Cold & Flu Guard Spray
Cold & Flu Guard Spray

Antiviral studies carried out by Utah State University – Institute for Antiviral Research Virucidal Assay – found that Flavobac can deactivate 99.99% of SARS-CoV-2 that cause Covid-19 (including variants delta, beta and gamma) within one minute of exposure. All other major airborne viruses and bacteria such as those that cause flu and colds were inactivated within 5 minutes of use.[i]

In contrast, Cold & Flu Guard does not harm beneficial bacteria in the nose or mouth and, in fact, actually promotes the growth of desirable microbiome bacteria in the oral cavity. [ii]

What are flavonoids?

Flavonoids belong to a class of plant substances that contribute to the colour, taste and aroma of many fruit, vegetables and flowers. They also have antimicrobial properties that protect plants from viral, fungal and bacterial attacks. They are found in almost every plant such as vegetables, fruits, nuts, seeds and tea but only small amounts are absorbed from the diet into the body in an active form.

At least 6000 different flavonoids have been identified (some sources say over 9000) and some of these can act at various stages of viral infections to inhibit viral growth. [iii] Those that also have beneficial biological effects in humans are often referred to as bioflavonoids and are one of the reasons why some fruit and vegetables have gained a reputation as “super foods.”   

The bioflavonoids present in Cold & Flu Guard are derived from the pith of bitter oranges which gives the spray a lovely mild, orange flavour.

Research findings

The health benefits of bioflavonoids have been intensively studied. In the last 5 years alone, over 9,000 papers have been published describing the antiviral properties of bioflavonoids plus over 16,500 papers describing their antibacterial activity.[iv]

As well as their ability to kill respiratory viruses, bioflavonoids can enhance immunity and suppress the production of excess inflammatory cytokines. These cytokines, released by over-stimulated immune cells contribute to some of the dangerous complications of viral infections such as Covid-19. Bioflavonoids also interfere with the process of viral replication to help stop them infecting and multiplying within human cells.

Flavobac was first tested against influenza A virus and the rhinoviruses that cause the common cold back in 2004 and the viruses causing swine and avian ‘flu in 2009. These studies found the flavonoids present could kill 99.99% of these viruses within 5 minutes. In October 2020, it was also tested against SARS-CoV-2 viruses which it killed within one minute of exposure.

In January 2021, research published in the journal Phytochemistry Reviews concluded that flavonoids are a promising and safe therapy against COVID-19.[5]

Flavobac effectiveness at killing respiratory viruses
Effectiveness at killing respiratory viruses
Flavobac effectiveness at killing coronavirus variants
Effectiveness at killing Coronavirus variants

The reason that Cold & Flu Guard remains in the nose and mouth for so long is because it contains glycerin and a lubricating ingredient, hyaluronate, which together act as a biofilm to attract and trap pathogens. The bioflavonoids present can then bind and inactivate the infecting microorganisms for the body’s natural cleansing processes to expel. The spray should be used 2 to 3 times a day for full protection.  

Spray into nose and mouth

How to use Cold & Flu Guard

Using Cold & Flu Guard spray which contains natural citrus bioflavonoids will help to protect against viral respiratory infections by killing the viruses in the mouth and nose. For example, it can be used before attending events or crowded places where you might be exposed to cold and flu viruses such as in offices, supermarkets or other stores, buses or trains, schools and sports’ venues.

The spray can be used together with the wearing of a face mask as double protection. It can also be used if you develop symptoms of a viral infection to help alleviate the severity of symptoms and to reduce the number of viruses we breath out so we are less infectious.

For adults and children aged 5 years and over:

  • Shake well before each use.
  • Apply 1 – 2 sprays per nostril (avoid deep aspiration as you want the spray to remain in the nose.  It will sting for a few second and clear)
  • Repeat 1 – 2 sprays in the mouth.
  • Use 2 to 3 times per day.

Cold & Flu Guard is available in many countries via or Amazon in a 50ml bottle which will last you well over a month if used every day. 

Ingredients: water, glycerine, xylitol, polysorbate 20, ethanol, bioflavonoids, mint flavour, disodium phosphate anhydrous, stevia, cetylpyridinium chloride, sodium hyaluronate.

NB Do not use of allergic to any of the ingredients. If pregnant, consult your doctor.








[v] UTAH State University Virucidal Assay against SARS-CoV-2, Institute for Antiviral Research, SARS2-378. January 4 2021–Data on file

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