Grapefruit Seed Extract, A Natural Antibiotic?

Tara McLoughlin Supplementation Leave a Comment

A natural antibiotic can come in all shapes and sizes, in this case, Grapefruit Seed Extract (GSE) but does it actually work as?  It is natural? Is it safe? There are many questions and even more opinions on the matter so why not add mine to the mix?  

I’ve spent considerable time researching these questions.  There are certainly plenty of people looking for clear cut answers. My motivation for writing this article is, as always, to provide readers with additional points of consideration when looking for alternative medicine and in this case, a natural antibiotic.  

What is Grapefruit Seed Extract?

Grapefruit Seed Extract, also known as GSE, is a compound derived from the seeds of grapefruit that has long been used for it’s antimicrobial properties.  The commercialized version of GSE is known as Citricidal.

Generally speaking grapefruit seed extract is made through the processing of grapefruit seeds and pulp with the addition of glycerin.  Glycerin is a colorless, odorless, viscous liquid that is sweet-tasting and found to be non-toxic. It is widely used in the food industry as a sweetener and humectant in pharmaceutical formulations.

The production of some commercial versions of GSE can include:

  1. Grapefruit pulp and seed is dried and ground into a fine powder.
  2. The powder is dissolved in purified water and distilled to remove the fiber and pectin.
  3. The distilled slurry is spray dried at low temperatures forming a concentrated flavonoid powder.
  4. This concentrated powder is dissolved in vegetable glycerine and heated.
  5. Food grade ammonium chloride and ascorbic acid are added, and this mixture is heated under pressure. The amount of ammonium chloride remaining in finished Citricidal is 15-19%; the amount of ascorbic acid remaining is 2.5-3.0%.
  6. The ammoniated mixture undergoes catalytic conversion using natural catalysts, including hydrochloric acid and natural enzymes. There is no residue of hydrochloric acid after the reaction.
  7. The slurry is cooled, filtered, and treated with ultraviolet light.

In this example, there are other additives introduced to the process (hydrochloric acid and ammonium chloride). The final composition of the extract is made up of about 60% polyphenols in the form of diphenol hydroxybenzene, a chemical classified as a quaternary ammonium chloride-- as is benzethonium chloride.  In fact, it is nearly chemically identical to benzethonium chloride. This is a major topic of controversy as benzethonium chloride is not approved in the U.S. for internal use!!

Considering the number of processing steps as well as the inclusion of additives, I would argue that Grapefruit Seed Extract resulting from this particular process in not natural by definition.  That is not say that all GSE’s are created equal.  This is where being an educated consumer applies!

Use as a natural antibiotic

The main elements in grapefruit seeds thought to be responsible for its ability to kill infectious agents are chemical compounds (polyphenols) known as limonoids and naringenin. Another possible reason for this compound’s ability to fight bacteria is it’s low pH (5.5), providing a relatively acidic environment, prohibiting bacterial life.

Several studies, such as this one, have shown GSE effective as a natural antibiotic in treating bacterial infections such as:

  • Staphylococcus (aureus, epidermidis, haemolyticus, capitis, sciuri, salivarius,)
  • Enterococcus (casseliflavus, faecalis, faecium)
  • Pseudomonas (aeruginosa, fluor putida)
  • Providencia (rettgeri, stuartii)
  • Morganella morganii
  • Escherichia coli
  • Klebsiella pneumoniae 
  • baum/haem 
  • Enterobacter taylorae

There are versions of Grapefruit Seed Extract that have been tested free of benzethonium chloride.  I have personal experience with one such product, Pure Encapsulations - Grapefruit Seed Extract.  The product page indicates it to be free of benzethonium chloride. I, literally, don’t go without this in my medicine cabinet nor do I travel anywhere without it securely in my suitcase.  I can’t tell you the number of times that I have avoided illness simply by taking it twice a day for three days at the onset of symptoms. I have used this for head, chest and gut bugs and have not been sick in any significant way for well over two years.

Other benefits

Grapefruit seed extract has a wide variety of known uses, aside from that as a natural antibiotic, medicinal and otherwise. 


  1. Fights Candida
  2. Fungal infection treatment
  3. Athletes feet and nail fungus remedy
  4. Acne treatment
  5. General antimicrobial
  6. Promotes a healthy GI tract


  1. Mouthwash
  2. Ear wash
  3. Fruit & veggie wash
  4. In laundry
  5. In carpet cleaners
  6. Sterilizing and disinfecting operating rooms
  7. In nebulizers
  8. In humidifiers 
  9. As a preservative
  10. Disinfecting surfaces 
  11. In hot tubs and swimming pools 
  12. Farming — In animal feed

    Immune Tree - The Official Brand

    Caution & controversy


    One main controversy stems from the detection of synthetic chemicals, namely, benzethonium chloride and triclosan in Grapefruit Seed Extract product.  There is much debate around the safety of these compounds when taken internally. As I am not a chemist, I can’t speak one way or the other but I, personally, use a GSE product clear of these chemicals.  I do not recommend talking a Grapefruit Seed Extract product not shown to be free of synthetic chemicals!

    Long Term Use

    Grapefruit Seed Extract is known for promoting overall gut health.  Having said that, there can be too much of a good thing. I do not recommend long term use of GSE without significant breaks between uses as it can deplete the good bacteria as well!  I typically double my probiotic consumption if I need to take GSE for longer than one week (which is rare).

    Talk to your doctor

    It is good practice to consult your doctor when adding supplements to your diet. In the case, it is especially true if you:

    • Are Pregnant or breastfeeding
    • Have known medication allergies
    • Are talking blood thinners or medicines used post-organ transplant
    • Have high blood pressure
    • Are taking prescription drugs. Grapefruit Seed Extract is derived from grapefruit which have known drug interactions.

    Here’s the bottomline. Each and every one of us has to evaluate the available information and make a decision on the use of GSE as an alternative remedy to infections.  Similarly to deciding on the use of pharmaceuticals, the benefits and risks must be weighed, individually, because our circumstances are all different.  As with most things, more studies are needed!!! 

    For me, personally, I find the benefits of using Grapefruit Seed Extract outshine the risks, as we know them today.  You must make your own decision.  

    Find out about another great natural remedy, Benefits of CoQ10 including Anti-Aging .

    Take care and, as always, stay healthy!


    *Remember to check with a healthcare professional before making changes to your diet, including the introduction of supplements. This information is for educational purposes only and is not intended to diagnose or treat any medical condition.

    **These claims have not been evaluated by the Food and Drug Association.

    Research & Expert Opinions

    The Effectiveness of Processed Grapefruit-Seed Extract as An Antibacterial Agent

    The Truth About Grapefruit Seed Extract

    6 Grapefruit Seed Extract Benefits You Won’t Believe

    7 Grapefruit Seed Extract Uses, Plus Dangers to Beware Sample records for compounds benzalkonium chloride

    The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity.