Oregano instead of antibiotics?

veterinary news

It sounds wacky, doesn’t it?  Who would think that the spice oregano could take the place of antibiotics?  Is this just a silly internet rumor?  Or is there any truth to the idea that oregano can replace antibiotics?

oreganoI came across an article from the NY Times where a farmer describes using oregano in place of antibiotics in chicken feed.  My first thought upon reading this is that people are going to be wondering whether or not oregano can be used for cats and dogs who are in need of antibiotics.   There is some evidence to show that oregano has antibacterial properties.  Will it be replacing man made antibiotics?  Read on and see what I discovered.

Why Oregano?

It is believed that Oregano has some effectiveness against certain bacteria.  I was able to find a number of research articles that studied whether or not oregano could act as an antibiotic.

Most of the studies looked at something called OEO (Oregano Essential Oil).  This is an oil that is made from oregano.  It is a much more concentrated form of oregano than oregano leaves.  (See below for a study that looked at the oregano leaf).  This study found that OEO had decent effectiveness against certain types of E. Coli bacteria.  They found that when they administered OEO to chickens along with traditional antibiotics, the dose of antibiotic needed to control infection was lowered.  Also, the addition of OEO caused the chickens to show fewer side effects to antibiotics.  This is a good thing!

Another study, showed that OEO was effective against several types of bacteria.  They even concluded that a commercial blend of oregano oils, rosemary oils and others could be used in the place of antibiotics in the feed of chickens.

Oregano Oil vs. Oregano Leaf

Almost every study I could find, however, discussed the benefits of Oregano Essential Oil.  But what about the oregano leaf that you and I have in our kitchen?  I did find one study that examined how effective the dry oregano leaf was when used in the place of antibiotics in chickens.  The study found that there was no benefit at all to using oregano leaf.  The chickens on antibiotics were healthier and grew larger than those given the oregano leaf supplement.


Oregano instead of antibiotics for cats and dogs?

But what about in cats and dogs?  Should we be using oregano instead of antibiotics?  Is it a natural remedy?

The truth is that no one knows for sure how effective oregano is against bacteria in cats and dogs.  I could not find any studies that have been done on oregano use in cats and dogs.  No one knows what kind of dosage could potentially be effective.  I did find some information that was very helpful though:

  • There are some natural vets who believe that using Oregano Essential Oil topically on an infected skin lesion could be helpful.  However, what they have found is that this oil really stings when used on cat or dog skin.  Also, if it is placed on the skin of an animal they are likely to lick it and end up with burns on their tongue or mouth.
  • I found one report of a cat who had severe burns on his scrotum because of contact with OEO.
  • If OEO is given orally (by mouth) to cats and dogs it can cause burns inside the mouth and serious digestive problems.
  • There have been several reports of cats who refused to eat for several days after being given OEO by mouth.

What this information tells me is that it likely isn’t safe to treat animals with OEO.

But what about oregano leaf?  As mentioned above, studies in chickens showed that oregano leaf did not work in chickens unlike the oregano essential oil.  There’s no harm in adding a small amount of oregano to your pet’s food (if they will eat it).  But, a small amount is not going to have antibacterial properties.


I would definitely not recommend using oregano as a substitute for antibiotics in cats and dogs.  It’s not likely to work.  Plus, if you use the oil formulation it could be quite harmful.

Your thoughts?

I’d love to hear your thoughts on this article.  Please leave a comment below!

About the author

Dr. Marie

Dr. Marie is a veterinarian treating dogs, cats, and pocket pets. Click here to ask Dr. Marie a question.

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