Oil of Oregano for Traveler’s Diarrhea

Giardia_Lambdia_Protozoa_Small_Intest_ParasiteOil of Oregano for Traveler’s Diarrhea

by Jeffrey Dach MD

Patti is a 54 year old insurance executive doing well for many years on her bioidentical hormone replacement program. However, this year she picked up a “GI bug” after an “Island Cruise”, reporting symptoms of diarrhea, abdominal pain, gas, bloating, and generalized malaise. In order to eradicate the offending organism, Patti’s “GI bug”, we need to know exactly which organism we are dealing with, so we can select the correct anti-microbial drug. There is a handy test for this.

Causes of Traveler’s Diarrhea

There are many causes of travelers diarrhea including pathogenic bacteria such as Salmonella,  Shigella and Campylobacter species, listed here: Diagnosis and Management of Food Borne illness.

In addition, there are various protozoa intestinal parasites such as Giardia lamblia, Entamoeba histolytica, Dientamoeba fragilis, Cryptosporidium parvum, Cyclospora cayetanensis and Blastocystis hominis.

We would like to know which organism is the offending culprit in order to choose the most most effective treatment modality.  How can we identify the offending organism ?

There is a handy test for this, giardia lambdia vrdoljakthe GI-FX from Genova,   a home stool collection kit.  Once the stool sample is collected and sent into the Genova lab, testing is performed looking for microbial organisms with PCR-DNA testing.

This GI-Fx test is able to accurately identify presence of bacterial, fungal and parasite DNA in the stool sample.  Once a pathogenic organism is identified, the lab will also run a sensitivity panel looking at antibiotic and botanical sensitivities to guide with treatment.

Giardia_lamblia_SEMPatti’s GI-Fx stool test demonstrated Giardia Lambdia, a common intestinal parasite which was sensitive to Oregano oil.

Oregano oil is a botanical which contains the plant essential oil Carvacrol and thymol, both  more effective at killing Giardia than commonly used anti-parasitic drugs. (1-6)

Pattie started her course of ADP Oregano Oil from Biotics Research, and within 3 weeks reported feeling much better.  She was started on her probiotics and within 6 weeks she was back to normal.

Antifungal Properties of Oregano Oil for Onchomycosis

Antifungal properties of Oregano Oil makes it a suitable treatment for Nail Fungus (Onchomycosis). (11-20)

Here is a link to Buy Oregano Oil on Amazon.
Here is a LINK to videos on the Genova GI-Fx test
Here is a link to the instruction for the GI Effects Stool Test Kit: Click Here
Jeffrey Dach MD
7450 Griffin Road, Suite 190
Davie, Fl 33314

Links and References:

Treating infections naturally Dr Ramsey

Header Image and third image courtesy of wikipedia A SEM micrograph of the small intestine of a gerbil infested with Giardia reveals a mucosa surface almost entirely obscured by attached trophozoites.

Second image: Courtesy of science news .  Giardia Lambdia.

1) http://www.ncbi.nlm.nih.gov/pubmed/10815019
Phytother Res. 2000 May;14(3):213-4.
Inhibition of enteric parasites by emulsified oil of oregano in vivo.
Force M1, Sparks WS, Ronzio RA.
Oil of Mediterranean oregano Oreganum vulgare was orally administered to 14 adult patients whose stools tested positive for enteric parasites, Blastocystis hominis, Entamoeba hartmanni and Endolimax nana. After 6 weeks of supplementation with 600 mg emulsified oil of oregano daily, there was complete disappearance of Entamoeba hartmanni (four cases), Endolimax nana (one case), and Blastocystis hominis in eight cases. Also, Blastocystis hominis scores declined in three additional cases. Gastrointestinal symptoms improved in seven of the 11 patients who had tested
positive for Blastocystis hominis.

2) http://www.ncbi.nlm.nih.gov/pubmed/17024354
Parasitol Res. 2007 Mar;100(4):783-90. Epub 2006 Oct 6.
Effect of oregano (Origanum vulgare L.) and thyme (Thymus vulgaris L.) essential oils on Trypanosoma cruzi (Protozoa: Kinetoplastida) growth and ultrastructure.
Santoro GF1, das Graças Cardoso M, Guimarães LG, Salgado AP, Menna-Barreto RF, Soares MJ.
Author information

In the present work, we have investigated the effect of essential oils obtained from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) on growth and ultrastructure of diverse evolutive forms of Trypanosoma cruzi. Culture epimastigotes and bloodstream trypomastigotes were incubated for 24 h with different concentrations of oregano or thyme essential oils and with thymol (the main constituent of thyme), and the inhibitory concentration (IC)(50) was determined by cell counting. Crude extract of oregano essential oil inhibited epimastigote growth (IC(50)/24 h = 175 microg/ml) and also induced trypomastigote lysis (IC(50)/24 h = 115 microg/ml). Thyme essential oil presented IC(50)/24 h values of 77 microg/ml for epimastigotes and 38 mug/ml for trypomastigotes, while treatment with thymol resulted in an IC(50)/24 h of 62 microg/ml for epimastigotes and 53 microg/ml for trypomastigotes. Scanning electron microscopy of treated cells showed few morphological alterations at the plasma membrane. Observation by transmission electron microscopy showed cytoplasmic swelling with occasional morphological alterations in plasma and flagellar membrane. Our data indicate that oregano and thyme essential oils are effective against T. cruzi, with higher activity of thyme, and that thymol may be the main component responsible for the trypanocidal activity.

3) http://www.google.com/patents/US5955086
DeLuca, Daryl L., et al. “Oregano for the treatment of internal parasites and protozoa.” U.S. Patent No. 5,955,086. 21 Sep. 1999.

Pathogenic protozoa, such as Giardia lamblia, Entamoeba histolytica, Dientamoeba fragilis, Cryptosporidium parvum, Cyclospora cayetanensis as well as Blastocystis hominis, are recognized as pathogenic organisms. See Gugliemetti P et al, Family outbreak of Blastocystis hominis associated with gastroenteritis, Letter, Lancet 1989,vol. 2, 1394; Udkow MP et al., Blastocystis hominis: Prevalence in asymptomatic versus symptomatic hosts, JID 1993, 168:242-4; Zierdt CH, Blastocystis hominis, Past and Future, Clin Microbiol Rev 1991; 4:61-79; Wilson K, et al., Blastocystis hominis infection: signs and symptoms in patients at Wilford Hall Medical Center, Military Med 1990; 155:394-6; Waghorn DJ, et al: Clinical significance of Blastocystis hominis. Letter. Lancet 1991: 337:609; O’Gorman M. et al: Prevalence and characteristics of Blastocystis hominis infection in children, Clinical Pediatrics, 1993; 32:91-96.

Many parasites that reside in the gastrointestinal tract cause gastrointestinal signs and symptoms, such as abdominal pain, bloating, diarrhea, and secondary carbohydrate intolerances including lactose intolerance and unexplained weight loss. See Jones JE, Signs and symptoms of parasitic disease, Primary Care 1991; 12:1-12.

The fecal-oral route of infection is common and poor hygiene among food handlers has increased the prevalence in some areas.

Treatment of parasitic infections typically relies on a series of medications including tinidazole, metronidazole, quinacrine hydrochloride, iodoquinol and similar compounds. These can have significant side effects, as cited in the Physicians’Desk Reference , 49th Edition, Medical Economics Data Production Co. 1995,including pages 1114, 2199, 2322-2324.

In particular, oregano (Oreganum vulgare, Mediterranean oregano) a common culinary herb, and its associated essential oil have been shown to inhibit the growth of many kinds of bacteria. See Belaiche P, Traite de Phytotherapie et d’Armoatherapie, Tome 1. L’Aromatogramme, Maloine SA Editeur, 1979, pp 92-100.

In addition, the oil of oregano is a potent inhibitor of yeast and fungi, including the potential pathogen, Candida albicans. See Stiles JC et al. , The inhibition of Candida albicans by oregano, J Applied Nutr 1995; 47:96-102; Sivropoulou A et al. , Antimicrobial and cytotoxic activities of Origanum essential oils, J Agric Food Chem 1995; 44: 1202-1205.

The term “parasite” is intended to encompass protozoa, including amoebae and flagellates, as well as multicellular parasites, such as helminths (roundworms) and platyhelminthes (flatworms), which reside within the animal host. The invention is especially applicable to intestinal parasites.

Intestinal amoebae include Entamoeba hartmanni, Blastocystis hominis and Endolimax nana, as well as Entamoeba histolytica, which is a well known cause of dysentery.

Intestinal flagellates include Giardia lamblia, Dientamoeba fragilis, and Trichonomas hominis.

Other intestinal protozoa that cause food-associated parasitic infections include Entamoeba polecki, Sarchocystis hominis, and Toxoplasma gondii (from food and water contaminated by cat feces).

Intestinal helminths include parasites that can be transmitted by eating raw fish and meat.

Nematodes (roundworms) include Anasakis species, Ascaris species, Trichinella spiralis (trhininosis) and Ancyclostoma species (hookworm), Trichuris trichiura (whipworm), and Enterobius vermicularis (pinworm).

Cestodes are tapeworms. These include Diphyllobothrium latum, Spirometra species, Taenia species (from poorly cooked pork and beef) and Hymenolepsis species (from grains contaminated by meal worms infected by rodent feces).

Trematodes are flukes. Clonorchis sinensis, Opisthorchis viverrini and O. flineus represent liver flukes. Schistomsoma haematobium and related species are well established pathogenic organisms.

Intestinal flukes include Heterophyes heterophyes, Metagoniumus yokogawai, and Echinistoma ilocaneum.

Patients are treated with preparations of the oil of oregano so that the oral dosage is in the range of 50 mg to 500 mg or more daily for several weeks, typically four to six weeks, until analysis, typically a fecal analysis, reveals the absence of the parasite in question. In a clinical trial of the invention, after 14 days of treatment with oil of oregano, patients were further administered Lactozyme, a preparation of Lactobacillus acidophilus and Bifidobacterium bifidus from Biotics Research Corporation, to provide a total 10 to 12 million organisms three times daily, just before meals.

Treatment protocol

Patients were administered 5 tablets of the above-described composition (trade named A. D. P. ). from Biotics Research Corporation, three times a day before meals for one week. The A. D. P. preparation provides 50 mg standardized oil of oregano (from the culinary herb, Oreganum vulgare) as an emulsified, sustained release form.

After one week of treatment, the dosage of A. D. P. was reduced to three tablets, three times daily. This schedule was continued for another four to six weeks. After 14 days of treatment with oil of oregano, patients were administered Lactozyme, a preparation of Lactobacillus acidophilus and Bifidobacterium bifidus from Biotics Research Corporation, to provide a total 10 to 12 million organisms three times daily, just before meals.

Eight of the patients initially found to have parasites tested negative after treatment according to the oil of oregano protocol. Parasites were eradicated in 72. 7% (8/11) of the test population. This included five patients who initially had Blastocystis hominis, two patients with Entamoeba hartmanni and one patient with Endolimax nana.

In addition, five patients initially tested positive for Candida species and four tested positive for Geotricum. After treatment, none of these patients tested positive for these organisms.

4) http://www.ncbi.nlm.nih.gov/pubmed/16425064
Parasitol Res. 2006 May;98(6):557-60. Epub 2006 Jan 20.
Oregano (Lippia spp.) kills Giardia intestinalis trophozoites in vitro: antigiardiasic activity and ultrastructural damage.  Ponce-Macotela M1, Rufino-González Y, González-Maciel A, Reynoso-Robles R, Martínez-Gordillo MN.

In the world, giardiosis is still a very important parasitic disease; only in Asia, Africa and America, there are more than 200 million of infected people in a year. The usual treatments are drugs that produce undesirable secondary effects, perhaps favouring the resistant strain selection. One alternative is to research compounds from plants used as antidiarrhoeic or antiparasitic in the traditional medicine. In a previous work, we found that Lippia beriandieri (Oregano) revealed to be more potent than tinidazole, a common antigiardiasic drug. In this current work, we tested the cell viability by re-culture and reduction of MTT-tetrazolium salts to MTT-formazan, and we showed the effect of oregano ethanolic extracts against Giardia intestinalis (synonyms: Giardia duodenalis, Giardia lamblia) trophozoites at concentrations ranging form 58 to 588 microg. We demonstrated the ultrastructural injury produced by oregano extracts in this parasite. Trophozoites lost their size and shape and showed damage in nucleus structure, perhaps by breaking the pattern of nucleoskeleton proteins.

5) http://www.ncbi.nlm.nih.gov/pubmed/21535822
J Food Sci. 2011 Apr;76(3):C512-8. doi: 10.1111/j.1750-3841.2011.02109.x.
Oregano: chemical analysis and evaluation of its antimalarial, antioxidant, and cytotoxic activities.  El Babili F1, Bouajila J, Souchard JP, Bertrand C, Bellvert F, Fouraste I, Moulis C, Valentin A.

GC-FID and GC-MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p-cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC50=2±0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC50=4.8±0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC50 of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.

6) Oregano Oil: Nature’s Super Germ Fighter.  By James South, M.A



7) http://www.heathernicholds.com/health/intestinal-parasite-symptoms
Intestinal Parasite Symptoms And Tips By Heather Nicholds

Intestinal parasite symptoms include:

gassy after meals
weak or no appetite at meals
fatigue or weakness
poor concentration
eyes are sensitive to light
facial coloring is noticeably pale
tingling in lips, fingers, arms and legs
chest pains
very rapid or slow heartbeat
slow reflexes
pain in your navel
eating more than normal but still hungry


8)  Parasites and the Gastrointestinal Tract  Leo Galland, MD Parasites Can Be Acquired Anywhere You don’t need to travel to get a parasitic infection.  The gastrointestinal tract is vulnerable to getting parasites anywhere, as I will explain below.

Last year I saw a patient who had returned from her Christmas vacation complaining of persistent dizziness and fatigue that had not improved for over a year.   Before visiting my office she had consulted three other doctors but no cause for the dizziness was found.   When I questioned her about the vacation, which took place at a Caribbean resort, I discovered that she had experienced a transient episode of diarrhea there and since returning home had been unusually constipated and gassy.   She had never mentioned these intestinal symptoms to a doctor before, because it was dizziness and fatigue that bothered her the most.

Testing for Parasites
I’ve seen many patients with chronic fatigue caused by intestinal parasites, so I had this woman tested at a specialized laboratory. The test revealed infection with a parasite called Giardia lamblia, a condition called giardiasis.

A Study on Chronic Fatigue Syndrome and Giardia

In 1991, my colleagues and I published a study of two hundred patients with Chronic Fatigue Syndrome and demonstrated active Giardia infection in 46 per cent. Most of the patients with giardiasis had only minor gastrointestinal symptoms but were really ill with muscle pain, muscle weakness, flu-like feelings, sweats and enlarged lymph nodes. In fact, 61 per cent of fatigued patients with giardiasis had been diagnosed elsewhere as suffering from chronic fatigue immune dysfunction syndrome (CFIDS), compared to only 19 per cent of fatigued patients without giardiasis. Cure of giardiasis resulted in clearing of fatigue and related ‘viral’ symptoms (muscle pain, sweats, flu-like feelings) in 70 per cent of cases, some reduction of fatigue in 18 per cent, and was of no benefit in only 12 per cent.

In 1990 I presented a paper before the American College of Gastroenterology which demonstrated Giardia infection in about half of a group of two hundred patients with chronic diarrhea, constipation, abdominal pain and bloating. Most of these patients had been told they had irritable bowel syndrome, which is commonly referred to as “nervous stomach”. I reached two conclusions from this study: (1) Parasitic infection can be a common event among patients with chronic gastrointestinal symptoms. (2) Many people are given a diagnosis of irritable bowel syndrome without a thorough evaluation.

9) http://www.drwisetravel.com/worm.html Mark Wise MD
After Your Return: Honey… I Passed a Worm!

10) http://www.adoptvietnam.org/travel/return.htm
Upon Your Return – Health Issues for International Travelers by Doctor Wise  By Doctor Mark Wise

Toe Nail Fungus

11) free pdf
Parashar, Bharat, et al. “Natural Therapy of Fungal Nail Disease.” The Pharma Innovation 1.4 (2012).

12) https://www.globalhealingcenter.com/natural-health/the-benefits-of-ozonated-olive-oil-for-toenail-fungus/
The Benefits of Ozonated Olive Oil for Toenail Fungus by Dr. Edward Group DC, NP, DACBN, DCBCN, DABFM
Last Updated on October 5, 2015

13) Zoric N1, Horvat I, Kopjar N, et al. Hydroxytyrosol expresses antifungal activity in vitro. Curr Drug Targets. 2013 Aug;14(9):992-8.

14) Valacchi G1, Zanardi I, Lim Y, et al. Ozonated oils as functional dermatological matrices: effects on the wound healing process using SKH1 mice. Int J Pharm. 2013 Dec 15;458(1):65-73.

15) https://www.pharmaceutical-journal.com/learning/learning-article/how-to-treat-fungal-nail-effectively/20205630.article?firstPass=false

16) How to treat fungal nail effectively
The Pharmaceutical Journal20 NOV 2018By Marion Yau, Anisha Soni, Win Leung Siu

17) https://www.ncbi.nlm.nih.gov/pubmed/12428445
Soković, M., et al. “Antifungal activities of selected aromatic plants growing wild in Greece.” Food/Nahrung 46.5 (2002): 317-320.

18) Essential oils of Origanum onites, Satureja thymbra, Salvia fruticosa (Greek sage), and Salvia pomifera subsp. calycina plants growing wild in Greece and their components carvacrol, camphor, and 1,8-cineole, were assayed for antifungal activity against 13 fungal species. Among the fungi tested were food poisoning, plant, animals and human pathogenic species. The oils presented various degrees of inhibition against all the fungi investigated. The highest and broadest activity was shown by the carvacrol content oils (O. onites and S. thymbra), while the oil of sage was the least effective. Carvacrol exhibited the highest and 1,8-cineole the lowest level of antifungal activity among the components tested.

19) https://www.ncbi.nlm.nih.gov/pubmed/11559104
Aligiannis, N., et al. “Composition and antimicrobial activity of the essential oils of two Origanum species.” Journal of agricultural and food chemistry 49.9 (2001): 4168-4170.

20) https://www.ncbi.nlm.nih.gov/pubmed/12722144
Ramsewak, Russel S., et al. “In vitro antagonistic activity of monoterpenes and their mixtures against ‘toe nail fungus’ pathogens.” Phytotherapy Research: An International Journal Devoted to Pharmacological and Toxicological Evaluation of Natural Product Derivatives 17.4 (2003): 376-379.

Jeffrey Dach MD
7450 Griffin Road, Suite 190
Davie, Fl 33314


Click Here for: Dr Dach’s Online Store for Pure Encapsulations Supplements

Click Here for:  Dr Dach’s Online Store for Nature’s Sunshine Supplements

Web Site and Discussion Board Links:


Disclaimer click here: http://www.drdach.com/wst_page20.html

The reader is advised to discuss the comments on these pages with his/her personal physicians and to only act upon the advice of his/her personal physician. Also note that concerning an answer which appears as an electronically posted question, I am NOT creating a physician — patient relationship. Although identities will remain confidential as much as possible, as I can not control the media, I can not take responsibility for any breaches of confidentiality that may occur.


Link to this article:http://wp.me/p3gFbV-1YO

Copyright (c) 2014 Jeffrey Dach MD All Rights Reserved. This article may be reproduced on the internet without permission, provided there is a link to this page and proper credit is given.

FAIR USE NOTICE: This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of issues of significance. We believe this constitutes a ‘fair use’ of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes.


Last updated on by Jeffrey Dach MD

Oil of Oregano for Traveler's Diarrhea
Article Name
Oil of Oregano for Traveler's Diarrhea
Oil of Oregano is actually more effective than anti-parasitic drugs for intestinal parasites such as Giardia Lambdia.

8 thoughts on “Oil of Oregano for Traveler’s Diarrhea

  1. Pingback: BioFilms in Chronic Rhino Sinusitis - Jeffrey Dach MD

  2. Pingback: URL

  3. Pingback: Coronary Calcium Score Benefits of Aged Garlic - Jeffrey Dach MD

  4. Pingback: Adverse Effects of Flouroquinolone Antibiotics - Jeffrey Dach MD

  5. Pingback: Aloe Vera the Medicinal House Plant - Jeffrey Dach MD

  6. Hello! :) Also I brought back Giardia from Nepal/India, have already had 3x antibiotics and they did not disappear. Next I would like to try OREGANO OIL, my sister has already bought some for me. But I am not sure how to take it – any advise on that??? Thanks a lot for your help! :) Miri

  7. Pingback: Antibiotic Resistant Super Bugs Are Killing US – Site Title

Leave a Reply