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Dynamic Chiropractic – May 7, 2005, Vol. 23, Issue 10

Oil of Oregano: Nature's Antibiotic and Anti-Fungal Supplement

By James P. Meschino, DC, MS

The healing powers of oil of oregano were virtually unknown in North America until the early 1900s, even though our ancestors have relied on its medicinal effects for thousands of years. Hippocrates wrote volumes on how to use this medicinal herb in the treatment of many conditions.

In recent years, oil of oregano has been largely investigated for its antimicrobial properties.

A unique blend of oil of oregano, known as the P73 wild oregano blend, has been the subject of several recent investigative studies that examined its ability to kill various viruses, bacteria, yeasts and other microorganisms known to adversely affect human health. The fungal-fighting properties of P73 wild oil of oregano are supported by research conducted at the Georgetown University Medical Center and led by Harry G. Preuss, MD.

The study by Dr. Preuss, et al., published in the journal Molecular and Cellular Biochemistry, tested the efficacy of oregano oil against the fungal infection Candida albicans (better known as a yeast infection). The researchers concluded that oil of oregano "can act as a potent antifungal agent against Candida albicans."1 Other experimental studies have shown that this unique blend of oil of oregano kills at least 30 different strains of harmful bacteria, such as staphylococcus aureus, as well as other microorganisms, including coronaviruses, which are the second most common viruses to cause the common cold. Coronaviruses can also cause pneumonia and other respiratory infections.2-6

The P73 oil of oregano blend has also been shown to kill the Helicobacter pylori (H. pylori) bacterium, which is known to be a causal factor in up to 90 percent of duodenal ulcers and 80 percent of stomach (gastric) ulcers. A small clinical trial initiated in 2003 demonstrated that the P73 oil of oregano blend showed positive results in patients with stomach and duodenal ulcers.

Antimicrobial Active Constituents

Oil of oregano is known to be a rich source of the volatile oils thymol and carvacrol, which have been shown to be largely responsible for enabling oil of oregano to kill various microorganisms under experimental conditions. Oil of oregano also contains other active constituents, including flavonoids and a host of vitamins and phytonutrients.

The P73 wild oregano blend represents the first oregano-based product to be tested under controlled scientific settings for its ability to kill a variety of common microorganisms associated with infectious conditions in humans. It has been created using a proprietary, evaporative technique on the edible oils. This technique used on the wild, mountain-grown oil of oregano, as well as on the other natural spice extracts, creates a potent and concentrated formula. The oregano species used to make this extract is 100 percent hand-picked Mediterranean oregano, and is produced by traditional methods of cold pressing and steam distillation. No chemicals are used to extract the active ingredients, helping to assure purity of the product.

When using 250 mg capsules of the P73 wild oregano blend as part of the complementary management of various infectious conditions, most experts suggest the following protocols:

  1. Colds, flu, acute bronchitis and sinusitis - two capsules every four hours at the earliest signs of a cold or flu bug (or sinusitis), to help abort the condition and/or minimize symptoms and duration.
  2. Chronic bronchitis and chronic asthma - two capsules twice per day until condition improves to a significant degree, and then reduce or eliminate the dosage, depending upon improvement.
  3. Chronic mono and chronic fatigue - two capsules twice per day along with other supplements to boost immune and energy systems.
  4. Candida and yeast infections - two capsules three times per day until significant improvement is realized, upon which a lower maintenance dosage should be followed, until complete resolution of the problem is achieved.
  5. Duodenal and gastric (stomach) ulcers - three capsules twice per day (can be taken in conjunction with other medicines aimed at killing the H. pylori bacterium).
  6. Acne and rosacea - oil of oregano can also kill the bacteria and skin mite associated with acne and rosacea, respectively. Some patients have seen improvement in these conditions when taking two capsules twice per day. A topical oil of oregano cream applied at night can further assist in these cases.

As a complementary supplement, oil of oregano can be used concurrently with other medications prescribed for the treatment of the aforementioned conditions, but should not be used as a substitute for these medications without consent of the attending physician.

Safety of Oil of Oregano

Toxicity studies indicate that oil of oregano is a very safe product and has not been associated with any serious side-effects or negative health outcomes in thousands of years of use. However, as is the case with most supplements, women who are pregnant or breast-feeding should not use oil of oregano capsules or topical products. If oil of oregano supplementation exceeds one month of continuous use, as may be warranted in some of the conditions noted previously, it may also be prudent to ingest functional foods containing live cultures of friendly bacteria, such as yogurt, to help maintain ideal levels of friendly gut bacteria. Although oil of oregano primarily targets undesirable bacteria and other hostile microbes in the body, it may also minimize the concentrations of friendly gut bacteria with long-term use. To guard against this possibility, regular ingestion of live friendly bacterial cultures from functional foods is recommended, as well as daily ingestion of prebiotics, which are proven to foster the growth of the friendly gut bacteria.


  1. Manohar V, Ingram C, Gray C, et al. Antifungal activities of origanum oil against Candida albicans. Molecular and Cellular Biochemistry 2001;222:111-117.
  2. V, Manohar, C Ingram, J Gray, et al. Antibacterial effects of the edible oil of oregano against staphylococcus aureus. Abstract 66: From the American College of Nutrition's 42nd annual meeting - Orlando, FL - Oct 3-7, 2001.
  3. Stiles JC, Sparks W, Ronzio RA. The inhibition of Candida albicans by oregano. J Applied Nutr 1995;47:96-102.
  4. Force M, et al. Inhibition of enteric parasites by emulsified oil of oregano in vivo. Phytother Res May 2000;14(3):213-4.
  5. Oreganol P73 and Oregacyn P73 have a direct killing effect and ability to stop replication of the human coronavirus in vitro. Research project conducted by Microbiotest, Inc. (Sterling, Va):
  6. Dorman HJ, et al. Antimicrobial agents from plants: antibacterial activity of plant volatile oils. J Appl Microbiol Feb 2000;88(2):308-16.

James Meschino, DC, MS
Toronto, Ontario

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