Grapefruit seed extract - the ultimate anti-microbial


In November 1996, while on holiday in Ireland, I spent an evening with a friend, a qualified nurse and a practising aromatherapist and reflexologist. As always, in her company, talk turned to the application of alternative remedies to support conventional medical practice. She handed me a small flier which spoke of a new remedy which had been gaining increased credibility in America, and which was now available from in Ireland. It spoke of an incredibly broad spectrum of applications: of anti-microbial, anti-bacterial, anti-fungal, antiseptic, anti-parasitic properties; low toxicity; low cost; bio-degradability. It spoke of a totally naturally occurring, and naturally processed food supplement, which has been available and untapped on this planet for at least 300 years, since the first grapefruit trees were discovered and identified on the island of Barbados. The product was grapefruit seed extract, and my friend was beginning to test out its claims.

On my return to the UK, I sought in vain for a retailer who had even heard of this wonder product, and, in desperation, phoned the Irish distributor who sent me a bottle and a book describing the properties, entitled Â?The Healing Power of Grapefruit SeedÂ?. Book and bottle arrived in mid-November, the busiest time of my working year, and a time at which I cannot afford either holidays or sickness. That evening, I came home from work with the makings of the flu which had been laying waste my colleagues, and keeping people who were never ill away from work of upwards of a fortnight. In one sitting I read the book and put the Grapefruit Seed Extract (GSE) to the test. I made up my normal cold remedy - honey, cider vinegar, hot water - and laced it with 10 drops of GSE. I also took 2000mg of vitamin C, and 2 Gelsemium 6 potency, which I have always found useful for the early abatement of flu, but, in spite of my precautions, I had very little expectation of escaping. An early night did nothing to ease my discomfort. I tossed and turned and snuffled and dozed into the early hours in increasing discomfort, concerned now that the infection would not end up on my chest and aggravate my asthma. About 3.00am I woke from a feverish doze pouring with perspiration and feeling decidedly unwell, and very dehydrated. After a drink of water and a cool sponge-over, I went back to bed full of apprehension, to fall into a dreamless and restful sleep, only broken by the sound of the alarm clock at 7.00. I felt rested, clear headed, and had no sign of the previous nightÂ?s fever, and only the remains of soreness in my nose and throat. The event was unprecedented, and I was, in fact, the only member of a 60 strong staff to escape the flu, and the resultant revolting cough. In fact, over the busy period, November to April, I fought off two more potential bouts of the particularly virulent flu which raged across the West Midlands, eventually succumbing to a mere head cold when I went on holidays unprepared in May!


Grapefruit has been known in this country since the 17th century when it was identified by botanists on the island of Barbados. The anti-oxidant effect of citrus has been known for even longer. However, the discovery of the additional properties of Grapefruit Seeds was made as recently as 1980.

Dr Jacob Harich, a keen gardener, as well as a physician, an Einstein Laureate physicist, and an immunologist specialising in the investigation of natural remedies, noticed that grapefruit seeds in his compost heap did not rot. His curiosity piqued, he decided to take a closer look, and discovered a substance concealed in the grapefruit seeds that appeared to be more effective, and at the same time less harmful, than any known antibiotic. Research subsequently uncovered a broad range of efficacy. The extract from the seeds was found not only to inactivate viruses, but also yeasts, other fungi and parasites.

The ideal anti-microbial?

·        broad spectrum - Research shows that GSE is effective against approximately 800 bacteria and virus strains, 100 strains of fungus and a large number of single cell parasites, far exceeding that of any currently known anti-microbial.

·        powerful and effective - GSE develops its antimicrobial activity with an average concentration of 1,000 parts per million - corresponding to about 8 drops in a glass of water. Research by an international research team compared the performance of GSE on 770 strains of bacteria and 93 fungal strains with 30 effective antibiotics and 18 fungicides, and found that GSE performed as well as all tested agents.

·        non-toxic - The non-toxic effect of GSE may be recognised in the effect on a drunken agricultural worker in Peru who, as the result of a prank, accidentally ingested 4 fl oz of the extract. Apart from clearing out all the parasites in his body ( of which there was a great number), he suffered no ill effects. Research indicates that a person weighing 180lbs ( approx. 13 stone) would need to ingest about 5.5 pints of a 50% solution of GSE in order to become severely poisoned.

·        non-weakening to the immune system - GSE can be used in treatment of a variety of immunodeficient diseases, as its broad spectrum anti microbial activity relieves the immune system of an enormous burden.

·        leave beneficial bacteria intact - This effect is most evident when GSE is used to treat Candida. Many proprietary Candida treatments affect not only the Candida, but also the intestinal flora which support recovery. Research has proven that GSE, taken in normal dosages, does not affect Bifidobacteria at all, and only insignificantly reduces Lactobacilli, despite its inhibiting effect on harmful intestinal bacteria. Thus creating the ideal environment to enable the body to restore its own balance.

·        naturally derived - GSE is made by grinding the seeds, together with a portion of the flesh membrane. The process is natural, and the result is natural, needing, by its very nature, no artificial additives to assure its stability or longevity. The product is retailed in diluted form consisting of 33% GSE and 67% vegetable glycerine, and all references to it assume this combination.

·        hypoallergenic - Most doctors could not establish any kind of allergic reaction in the use of GSE. However, about 3% to 5% of people are allergic to citrus fruit and could display an allergic reaction. Kiniesiologists, however, know that not everyone who has a citrus allergy is allergic to grapefruit. I have tested this with a friend who has a documented allergy to citrus, who uses 15 drops a day to control the pain and immobility of osteo-arthritis. She has built up her intake over a period of weeks with no harmful side effects, and a beneficial effect on her lifestyle.

·        cost effective -The product is natural, requiring no expensive processing, no expensive additives, and no expensive storage or packaging conditions. It is used in drops rather than litres. Bottles retail at around 6 UK pounds, and my bottle lasts me, with daily use, for 4 to 6 weeks.

·        backed up by solid scientific research - Â?The Healing Power of Grapefruit SeedÂ? refers to 24 different pieces of research which were evaluated before the book was published, a body of international research across a broad spectrum of applications, and over 100 publications, varying from books on general sale to esoteric articles in specialist press publications. The spectrum is international and continuous, drawing on the experience of a growing number of holistic practitioners who use GSE therapeutically.

Sample of Research




British Columbia Research Corp, Vancouver BC

Final Report Bacteriocidal Efficacy of Citricidal

EcoTrend, North Vancouver, BC, Canada

Bio/Chem Research Inc, Lakeport CA

Citricidal - Mechanism of Action and Evaluation as a Disinfectant

Own study

Bio Research Laboratories Inc, Redmond, WA

Bacteriocidal efficacy of Citricidal

J Harrison Esq, Eco Trend,

North Vancouver, BC

Brigham Young University, Provo, UT

Evaluation Report of the Inhibitory properties of Citricidal / Inhibition of Bacteria and Yeast by Citricidal

Bio Chem Research, Lakeport, CA

Institut Pasteur, Paris

In vitro study of the inactivation of HIV by Citricidal

Bio Chem Research, Lakeport, CA

US Department of Agriculture, Greenport, NY

Citricidal Effective against 3 Animal Viruses: Foot and Mouth Disease, African Swine Fever, Swine Vesicular Disease

Dr Jacob Harich, Lakeport, CA

Northview Pacific Laboratories Inc, Berkeley, CA

Citricidal Test: Acute Oral Toxicity

K Stryker Esq, Matsuhitu Chemical Corp, Carson City, NV

University of Georgia / College of Agriculture, Department of Poultry Science, Athens, Georgia

Citricidal as a Feed Preservative, Mold Inhibitor, Antioxidant and for use with Fish

Bio Chem Research, Lakeport, CA

Valley Microbial Services, Palo Alto, CA

Citricidal Inhibition of Growth of Campylobacter Jejuni and Helicobacter Pylori

Bio Chem Research, Lakeport, CA


The extract contains primarily bioflavinoids and glycosides in the form of naringin (naringenin rutinosid), isosacuranetin (didymin), neohesperidin, hesperidin, dihydrocampherol glycoside, poncirin, quercetin glycoside, campherol glycoside, apigenin rutinoside, rhoifolin, heptamothoxyflavone, nobiletin, as well as several proteins.

Research indicates that the active ingredients of the extract disorganise the cytoplasmic membrane of the pathogen, thereby preventing the uptake of amino acids. At the same time there is a leakage of the cellular content with low molecular weight through the cytoplasmic membrane. The pathogen is inactivated and dies. The time required is normally shorter than, or, at worst, equal to that of most comparable preparations for eliminating micro-organisms.

It has been proven highly effective against a broad spectrum of germs and fungi including E.Coli, Candida, Staphylococcus, Streptococcus, Salmonella, Pseudominas, Lactobacillus, Klebsiella, Shigella, Legionella, Chlamydia, Helicobacter, Herpes and Giardia lamblia

Therapeutic applications

GSE is used internationally in the following areas:

·        in Thailand, a water projects uses GSE as its main purification agent. 350 gallons to 1 million gallons of water will reduce coli bacteria to 1 per 100ml. (200 per 100ml is officially considered acceptable)

·        in South America, GSE is used to purify many public swimming pools. Its application is preferable to the use of chlorine because it is not decomposed by UV rays, gives off no harmful vapours, does not cause skin irritation, does not evaporate if the temperature rises, is active against a range of fungi, including athletesÂ? foot which flourish in the environs of a swimming pool, and leaves no toxic residues in the environment

·        in farming GSE has proven extremely effective. A Danish pig farmer reported losses due to Porcine Reproductive Respiratory Syndrome of 16 out of every 30 piglets born. GSE successfully eliminated this loss, and doubled his profits. It is also used in the treatment of mastitis in cows in preference to antibiotics. In Peru, deaths of alpacas from various infectious diseases were reduced from 50% to 2% by the substitution of GSE for conventional vaccination and antibiotics.

·        in hospitals in the USA it is used in the cleaning of bed linen and carpets and was endorsed by Jerry Skidmore, manager of Laundry Operations in the Florida Hospital as giving Â?complete protection from the fungal and bacterial infections that can be associated with linenÂ?. This result is regularly tested and proven. In higher concentrations GSE is used for sterilising and disinfecting operating rooms and medical equipment such as inhalers. In Sao Paulo, Brazil, the extract was reported as 100% effective as a post-operative disinfectant, attacking only the bacteria, and not the skin. This compared with 98% effectiveness for the usual measures, and 72% for alcohol.

·        in treatment of Candida, Dr Leo Galland of New York, who has prescribed GSE for the past 7 years has reported only 2 failures out of 297 cases. The bonus attaching to the use of GSE is that it can simultaneously detoxify the system of other fungi and bacteria often accompanying Candida. It should, however, always be used within the framework of a comprehensive programme, and under competent direction. Without the necessary attendant changes to diet and lifestyle, the initial cure is unlikely to be maintained. It is also important to apply the remedy in increasing doses, starting from a low base, to avoid HerxheimerÂ?s reaction when the fungi start to die off.

The preservative properties, combined with total absence of toxicity make GSE a superb household cleanser across the whole spectrum from floors to food. The same properties offer opportunities for its application in any area where hygiene is of paramount importance such as food retail outlets and catering establishments.

The attraction of this broad spectrum product to the practitioner is that it takes allows him to tackle several different problems with the same remedy, often yielding the result, even if it has not been possible to come to a comprehensive diagnosis. Additionally, it does not compete with existing remedies, but supports their activity.

Like all products new to the market, Â?proof of the pudding is in the eatingÂ?. As my casebook increases in size, and clients return for replacement bottles, and additional information, I become more and more convinced that this is NatureÂ?s gift to us for the new millennium.

Case studies







Dorothy C

Nov/Dec 96

continued to take daily maintenance dose of GSE and has had no need to use either becotide or ventolin, even in Ireland!

This is a totally unprecedented occurrence


Dorothy C

Nov 96

took 5 drops in honey & vinegar drink to treat onset of flu. Symptoms came to head overnight and disappeared totally over next 4 days. No time lost from work. No illness.

Subject was out of work for a week in February with same flu, and attendant asthma. Most of office went down and were off work for up to 2 weeks, coming back with bad cough.

Ear Ache

Phil E

Dec 96

Ear swollen and infected inside and totally occluded due to the introduction of external bodies. Deep seated infection, much pain. 3 drops in massage oil dropped into ear over 3 day period. Swelling reduced, pain reduced, infection came to surface and dried up.

Recurrence of infection from similar cause 3 years previously. Very difficult to clear up with conventional medicine.

Reflexology used to support


Niamh OL

Dec 96

Gargled with GSE and took single dose in honey and vinegar to combat onset of severe, and recurring tonsillitis. Condition did not develop, and has not recurred

No other treatment was taken concurrently other than normal doses of Vitamin C

Mouth Ulcers

Cathal OL

Jan 97

Mouth and throat severely ulcerated due to run down condition. Gargled with GSE and took internally, condition completely cleared up within week

The ulcers were responding to none of the usual treatments. Treatment was conducted in conjunction with a course of multi vitamins and rest

Helicobacter Pylori

Philip E

May 97

Endoscope diagnosis confirmed presence of H Pylori in stomach and duodenum. 10 drops GSE taken 30 minutes before eating, 3 times a day. Stomach discomfort ceased almost immediately. No recurrence of symptoms

GSE opted for in preference to anti-biotic treatment.

Reflexology after 3 weeks confirmed improvement in stomach, duodenum and improved flexibility of colon


Bill S

May 97

GSE was added to a home-made cough remedy consisting of honey, glycerine and cider vinegar, and taken at the onset of chronic bronchitis. Cough cleared up within 4 days.

This patient is prone to debilitating bronchitis often taking as long as a month to clear fully.

Sun Rash

Sally C

June 97

Several drops of GSE in cold cream were applied to itchy hives which result from exposure to the sun. Itching stopped almost immediately, hives disappeared within 3 days

Sally is red haired, and has been unable to tolerate the sun for some years. This has been a very good summer for her, and she now has a suntan!

Cold Sores

Dorothy C

July 97

GSE direct from the bottle was applied to a coldsore site as soon as tingling began. The cold sore developed into a large -approx. .5 of an inch -(and very painful) lesion over 3 days, dried up, broke and scabbed and was totally gone in 8 days

These coldsores are activated by exposure to strong sunlight and have never previously cleared up in less than 3 weeks!


Â?The Healing Power of Grapefruit Seed" by Shalila Sharamon & Bodo J Baginski Lotus Light Shangri-La

Other publications discussing the properties of GSE include "Beyond Nutrition", "Mothering", "The Third Option", "Alternative Medicine Digest", "Natural Health" (Magazines), and "Coping with Candida", Shirley Trickett; "The Allergy Problem", Vickey Rippere; "Parasites - the Enemy Within", Dr Hanna Kroeger; "The Cure for All Cancers - 100 Case Histories", Dr Hulda Regehr Clark;

For more information contact:

Holistic Alternatives, 10 Whitworth Drive, Randlay, Telford, TF3 2NN
or phone or fax on 01952 593193
or email on

About the author:

Article written by Dorothy Cronin

Author: Dorothy Cronin
Copyright © 2023 Dorothy Cronin. All rights reserved

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