Grapefruit / Citrus Seed Extract

Grapefruit seed extract (GSE) is truly a broad-spectrum natural antibiotic, capable of killing a wide variety of pathogens. Highly active against protozoa, bacteria, yeast and some viruses, it has been used for quite some time in the treatment of parasitic infections. It is nontoxic, generally hypoallergenic and can be administered for up to several months, which may be required to eliminate stubborn infections. GSE is sold both as “Grapefruit Seed Extract” and “Citrus Seed Extract”. Unless otherwise indicated on the label, these products are usually made from grapefruit seeds only.

GSE has been shown to be effective in treating hundreds of different organisms including: Shigella, Staphylococcus, Pseudomonas aeruginosa, Giardia lamblia, Diplococcus pneumoniae, Haemophilus influenzae, Mycobacterium species, Campylobacter, Candida albicans, Escherichia coli, Streptococcus, Salmonella, Klebsiella, Proteus, Cholera, Chlamydia trachomatis, Trichomonas vaginalis, Legionella pneumoniae, Helicobacter pylori, Herpes simplex 1, Influenza A2, and measles virus. GSE has been shown to kill both gram-negative and gram-positive strains of bacteria

Different products may vary in strength so you should follow the label or your doctor’s directions for any particular product. As concentrated solutions, they almost always require dilution, and a different dilution for different forms of application. Its bitter taste may be avoided by mixing it with carrot, vegetable, orange or grapefruit juice, or by taking it in capsule form usually just after a meal.

GSE preparations can be used both internally and externally.

  • External Use: GSE can be used externally as a disinfectant for both intact skin and to prevent infection in wounds. A study in Brazil found it to be 100% effective (at 100ppm) for skin disinfection when used as a pre-surgical prep compared to an effectiveness rate of 72% for alcohol and 98% for commercially available surgical soap.
  • Internal Use: GSE can also be used internally to treat chronic infections. It is often recommended at a rate of 3 times per day. Dosage should not exceed a total of 1500mg per day.
  • Nasal spray: Spray or use an eye-dropper to get several diluted drops into each nostril, and then swing the head quickly forward and down (so head is upside-down), forcing the liquid up into the nasal passages. Use up to six times per day.
  • Douche: GSE is added to one pint of water. Use twice a day as a douche for up to a week, in the treatment of yeast infections.


In much the same way that synthetic antibiotics can kill off the naturally occurring flora which exists in one’s body, so might GSE. Consequently, if this herb is to be used long-term in the treatment of a chronic infection, supplemental acidophilus may need to be taken. However, while one study found that GSE significantly inhibited E. coli, another normal inhabitant of the GI tract, it left the important and beneficial Bifidobacteria unchanged, and only slightly reduced the Lactobacilli species.

People using GSE should be aware that they may have, or may develop an allergy to this preparation. Persons with a known citrus allergy are at higher risk. Should you develop a rash or experience any other symptoms while using it, discontinue use immediately.


Grapefruit / Citrus Seed Extract can help with the following

Drug Side Effects  

Chemotherapy Side-Effects/Risks

August 9th, 2012. A glass a day of grapefruit juice lets patients derive the same benefits from an anti-cancer drug as they would get from more than three times as much of the drug by itself, according to a new clinical trial. The combination could help patients avoid side effects associated with high doses of the drug and reduce the cost of the medication.

Researchers at the University of Chicago Medicine study the effects that foods can have on the uptake and elimination of drugs used for cancer treatment. In a study published in August in Clinical Cancer Research, they show that eight ounces a day of grapefruit juice can slow the body’s metabolism of a drug called sirolimus, which has been approved for transplant patients but may also help many people with cancer.

Patients who drank eight ounces a day of grapefruit juice increased their sirolimus levels by 350%. A drug called ketoconazole that also slows drug metabolism increased sirolimus levels by 500%.

“Grapefruit juice, and drugs with a similar mechanism, can significantly increase blood levels of many drugs,” said study director Ezra Cohen, MD, a cancer specialist at the University of Chicago Medicine, “but this has long been considered an overdose hazard. Instead, we wanted to see if grapefruit juice can be used in a controlled fashion to increase the availability and efficacy of sirolimus.”

Grapefruit juice’s pharmaceutical prowess stems from its ability to inhibit enzymes in the intestine that break down sirolimus and several other drugs. The effect begins within a few hours of what the researchers refer to as “grapefruit juice administration.” It wears off gradually over a few days.

Cohen and colleagues organized three simultaneous phase-1 trials of sirolimus. Patients received only sirolimus, sirolimus plus ketoconazole, or sirolimus plus grapefruit juice. They enrolled 138 patients with incurable cancer and no known effective therapy.

The first patients started with very low sirolimus doses, but the amounts increased as the study went on, to see how much of the drug was required in each setting to reach targeted levels, so that patients got the greatest anti-cancer effect with the least side effects.

The optimal cancer-fighting dose for those taking sirolimus was about 90mg per week. At doses above 45mg, however, the drug caused serious gastrointestinal problems, such as nausea and diarrhea, so patients taking sirolimus alone switched to 45mg twice a week.

The optimal doses for the other two groups were much lower. Patients taking sirolimus plus ketoconazole, needed only 16mg per week to maintain the same levels of drug in the blood. Those taking sirolimus plus grapefruit juice, needed between 25 and 35mg of sirolimus per week.

“This is the first cancer study to harness this drug-food interaction,” the authors note.

No patients in the study had a complete response, but about 30 percent of patients in the three trials had stable disease, meaning a period when their cancers did not advance. One patient receiving grapefruit juice had a partial response – significant tumor shrinkage – that lasted for more than three years.

Although ketoconazole produced a slightly stronger drug-retention effect, grapefruit juice has the advantage that it is non-toxic, with no risk of overdose. “Therefore,” the authors wrote, “we have at our disposal an agent that can markedly increase bioavailability (in this study by approximately 350%) and, critically in the current environment, decrease prescription drug spending on many agents metabolized by P450 enzymes.”

Sirolimus was the first of a series of drugs, known as mTOR inhibitors, that were developed to prevent rejection of transplanted organs but that also have anti-cancer effects. As the first of its class, it was also the first to come off patent, making it less costly. “Further cost savings,” the authors suggest, could be realized “by combining the drug with agents that inhibit its metabolism.”

Because different people produce varied amounts of the enzymes that break down sirolimus, the effect of grapefruit juice can vary, but tests of enzyme levels may be able to predict how an individual patient will respond.

“The variation in potency of the grapefruit juice itself may be far greater than the variation in the enzymes that break down sirolimus,” Cohen said. An early version of the study used canned grapefruit juice, generously donated by a Chicago-based grocery chain. But tests of the product found it lacked the active ingredients. So the researchers shifted to a frozen concentrate product supplied by the Florida Department of Citrus. [Article adapted by Medical News Today from original press release.]


Parasite, Entamoeba Infection

In a series of almost 200 patients treated for giardia or entamoeba histolytica by a Dr. Parish and his associates over a two month period, grapefruit seed extract gave symptomatic relief more than any other treatment that was tried.


Dysbiosis, Bacterial

Citrus seed extract may be a desirable first line of treatment because of its broad spectrum of antibacterial, antifungal and antiprotozoan benefits. The usual dose required is 600-1600mg per day. Animal studies have shown no toxicity except for intestinal irritation producing diarrhea at very high doses. The mechanism of action is not known; there is no evidence of systemic absorption.


Yeast / Candida

Chronic candidiasis can be successfully treated with grapefruit seed extract according to the many clinics and medical practitioners now prescribing it. Dr Leo Galland, who prescribes it for chronic candidiasis, has reported treatment failure in fewer than 1% of cases, and considers it to be “a major therapeutic breakthrough for patients with chronic parasitic and yeast infections.”


Parasite, Giardiasis Infection

In a series of almost 200 patients treated for giardia or entamoeba histolytica by a Dr. Parish and his associates over a two month period, grapefruit seed extract gave symptomatic relief more than any other treatment that was tried.


Parasite, Dientamoeba Fragilis

Using a product called citramesia (contains grapefruit seed extract and wormwood), some have claimed a complete elimination of DF.



When dysbiosis is present, treatment with antibiotics or with a natural antibiotic derived from grapefruit seeds has produced major improvement in the GI symptoms of eczema patients and moderate improvement in the severity of eczema. One advantage in the use of grapefruit seed extract over conventional antibiotics lies in its antifungal activity. This agent adds a second therapeutic dimension and eliminates the possibility of secondary candidosis. The minimum effective dose of grapefruit seed extract for bacterial dysbiosis is 600mg per day.



Grapefruit or citrus seed extract has been reported to help.


Vaginitis/Vaginal Infection

Citrus seed extract is useful for vaginal candida infections. In a study done by the Universidad Autonoma de Nuevo Leon in Mexico, 20 women douched using grapefruit seed extract every 12 hours for 3 consecutive days. 15 patients were cured after the first treatment. Four patients received treatment twice to become symptom free and receive negative laboratory results and 1 patient repeated the treatment 3 times until the lab report came back negative.


May do some good
Likely to help
Highly recommended



See Protozoan


Microscopic germs. Some bacteria are "harmful" and can cause disease, while other "friendly" bacteria protect the body from harmful invading organisms.


A single-cell organism that may cause infection in the mouth, vagina, gastrointestinal tract, and any or all bodily parts. Common yeast infections include candidiasis and thrush.


Any of a vast group of minute structures composed of a protein coat and a core of DNA and/or RNA that reproduces in the cells of the infected host. Capable of infecting all animals and plants, causing devastating disease in immunocompromised individuals. Viruses are not affected by antibiotics, and are completely dependent upon the cells of the infected host for the ability to reproduce.


A substance that has a low capacity for inducing hypersensitivity (i.e., an allergic reaction).


Infection of the skin or mucous membrane with any species of candida, usually Candida albicans. The infection is usually localized to the skin, nails, mouth, vagina, bronchi, or lungs, but may invade the bloodstream. It is a common inhabitant of the GI tract, only becoming a problem when it multiplies excessively and invades local tissues. Growth is encouraged by a weakened immune system, as in AIDS, or with the prolonged administration of antibiotics. Vaginal symptoms include itching in the genital area, pain when urinating, and a thick odorless vaginal discharge.


Also known as Trichomonas vaginalis or "Trich", this is one of the most common sexually-transmitted diseases. It is caused by a parasite that thrives in the vaginal environment, usually transmitted by sexual contact but also in warm moist environments such as hot tubs. Trichomonas may affect not only the vagina but also the urinary tract of both women and men. Signs include: Vaginal irritation; a fishy odor; a greenish/yellow vaginal discharge; pain with intercourse and/or with urination. Some women may have no symptoms at all.

Helicobacter Pylori

H. pylori is a bacterium that is found in the stomach which, along with acid secretion, damages stomach and duodenal tissue, causing inflammation and peptic ulcers. Although most people will never have symptoms or problems related to the infection, they may include: dull, 'gnawing' pain which may occur 2-3 hours after a meal, come and go for several days or weeks, occur in the middle of the night when the stomach is empty and be relieved by eating; loss of weight; loss of appetite; bloating; burping; nausea; vomiting.

Herpes Simplex

An infection, often recurrent, caused by herpes virus type 1 and 2. It causes cold sores around the lips and mouth, and also causes painful blisters on the genitals and in the pubic area, thighs, and buttocks.


Parts Per Million. A measure of the concentration of a substance, usually in air or water.


Usually Chronic illness: Illness extending over a long period of time.


(mg): 1/1,000 of a gram by weight.


Herbs may be used as dried extracts (capsules, powders, teas), glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless otherwise indicated, teas should be made with one teaspoon herb per cup of hot water. Steep covered 5 to 10 minutes for leaf or flowers, and 10 to 20 minutes for roots. Tinctures may be used singly or in combination as noted. The high doses of single herbs suggested may be best taken as dried extracts (in capsules), although tinctures (60 drops four times per day) and teas (4 to 6 cups per day) may also be used.


A microflora (good bacteria) that acts as a digestive aid and lives in your intestines helping your body fight disease.


Pertaining to the stomach, small and large intestines, colon, rectum, liver, pancreas, and gallbladder.


Hypersensitivity caused by exposure to a particular antigen (allergen), resulting in an increased reactivity to that antigen on subsequent exposure, sometimes with harmful immunologic consequences.

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