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topic 15053

Boric acid, safe on humans?

A discussion started in 2002 & continuing through 2017 . . .


Ok I have read about using boric acid as a rinse for the eyes, the feet and a few other things. Is this truly safe? I am a daycare provider and I have heard people using 1 part boric acid with 1 part rubbing alcohol. Boric acid is used to kill roaches [linked by editor to product info] and ants so how can this be safe for use on humans? As you see I do not know much about boric acid. I know this is about metal finishing but this is where I read the info on Boric acid so any info would be of help.

Dawn A [last name deleted for privacy by Editor]
- Watertown, Wisconsin


I did a quick web search on "MSDS boric acid" and got 94 hits with plenty of info on all the fine details of the health and safety aspects.

But you're not putting rubbing alcohol in MY eyes, Dawn! I remember giving a woman a back rub with alcohol once when a few drops ran down too far. Put a drop on an open cut or a mucous membrane to just imagine what it would be like in your eyes :-)

I've used boric acid in my eyes, but certainly no rubbing alcohol. Please ask your pharmacist. Good luck.

Ted Mooney, Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


Err...anything that ends with the word "acid" would make me very wary of putting it in my eyes!

Marc Green
Marc Green
anodizer - Boise, Idaho

(I'm not a doctor, but I play one on TV)


If you read the label of boric acid, it says it is an eye irritant. Rubbing alcohol, when applied to the eyes in a high enough dosage, can cause blindness. I've heard of boric acid being used as a disinfectant on a cut on your skin, but please consult your physician. Boric acid is toxic.

Anthony H [last name deleted for privacy by Editor]
- Atlanta, Georgia


I know from personal history that Boric Acid is totally safe, and and is in fact medicinally beneficial for the eyes, WHEN USED IN THE CORRECT DOSAGE, which is 1.9%, or less, of total volume.

The greatest number of postings on the internet are aimed at helping consumers handle Boric Acid in its full-strength state; when properly diluted, it is not an eye-irritant. In the same way, saline solution (salt) is beneficial to eyes; in this case the salt is used in a diluted form; but full-strength salt, if put into the eye, would be very irritating.

Marynell K [last name deleted for privacy by Editor]
- Arcadia, California


I see some eyewash solution for sale on the net which say they are 2.5% boric acid, so we're in the same ballpark, Marynell. And Paracelsus long ago told us that the difference between a medicine and a poison was the dosage.

But I think Dawn should be using commercial eyewashes rather than trying to make her own from boric acid for several reasons: To get the concentration right; to be sure there aren't undissolved granules that could scratch the cornea; to be sure it's USP grade instead of some impure material made for industrial use; to be sure the water is properly preserved and bacteria won't grow in the eyewash . . . and probably a few other reasons if we thought about it a while.

I suggest that people look up "Boric Acid Eye Wash [linked by editor to product info]" for their shopping, rather than "boric acid".

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


My mother would make a boric acid solution to wash our eyes with anytime we got an eye infection. Always took care of the infection and we had no problems from it at all. Also we had kittens and if they got infections in their little eyes we used the solution on them and it would clear them right up. It doesn't burn at all and feels just like having clear water put in your eyes, but it works great.

Sharon P [last name deleted for privacy by Editor]
- Rogers, Arkansas


OK I finally saw the answer I was looking for but no useful proportions. My mother also used this eye wash for us when ever we had a "cold in our eyes" i.e., lids crusted shut. It is a home remedy in danger of being lost if we can't get the recipe. Since I am not good at math and still confuse fluid ounces with dry ounces, give me a recipe that measures ounces of sterile water to teaspoon fraction!

Judi A [last name deleted for privacy by Editor]
- Hapy Camp, California


I'm all in favor of preserving the knowledge of home remedies, Judi! In this age of Frankenfood [link is to Wikipedia article], and crops engineered to produce sterile seed, and of DRM [link is to Wikipedia article]technology which may soon prevent access to any knowledge not approved by a handful of corporations, it's very important to preserve the old knowledge.

This thread implies that the proper proportion is 1.9 to 2.5 percent by weight. But people can't safely formulate from a poorly recalled highly selective particle of knowledge. If someone wants to research the subject in old books, that would be great! But then stick to the old book, not an internet reposting. Internet prowlers of the sort who write viruses should not be relied upon for what to put in our eyes. Our grandparents may have filtered the solution through gauze or followed other precautions. If you just mix crystals of commercial boric acid with water, with no knowledge of the old ways, maybe it's possible to scratch your cornea?

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

An Old Fashioned Recipe Book

The Old Herb Doctor

Folk Remedies That Work

Oddball Ointments, Powerful Potions, ...


I had similar questions about boric acid, especially when I purchased it and saw the POISON label. However, I checked with my pharmacist who swears by it as as a "cure" for vaginal yeast infections. It also used to treat eye infections when diluted. You will find it in almost all eye washes, if you check the labels of those products.

I recall my mother using it when I was young for "medicinal purposes" but we also used to get rid of roaches and ants. Go figure. Strange but true.

I purchased it in powder form to use in treating ear infections in my English 'Springer Spaniel. The formula can be found at many pet sites that have forums for medical treatment of different problems. It is as follows:

Blue Power Ear Wash Recipe

16 Oz. Isopropyl Alcohol [linked by editor to product info at Amazon]
(or Witch Hazel [linked by editor to product info at Amazon])

4 Tablespoons Boric Acid Powder [linked by editor to product info at Amazon]

16 Drops Gentian Violet [linked by editor to product info at Amazon] Solution 1%

Mix together in alcohol bottle and shake well.

Please shake this solution every time you use it to mix the Boric Acid Powder. Either a baby ear syringe or a plastic squirt bottle work well for putting the solution in the ear.


Evaluate condition of ears before treating and if the are inflamed and sore do not attempt to pull hair or clean out ear at all. Just flush and then wait until inflammation is gone, which will be about two days. Warm the solution and shake the bottle each time before using. The dogs will accept the treatment much better if you warm it up for them.

Flood the ear with solution (gently squirt bottle).

Massage gently, wipe with 100% cotton pad.

On first treatment: flood the ear twice, wipe with a pad, and leave alone without massage.

The dog will shake out the excess, which can be wiped with a tissue. (Note: the Gentian Violet [linked by editor to product info at Amazon] does stain fabrics so you're best to do this outdoors.)

Treat 2x per day for the first week to two weeks, depending upon severity of ears.

After the 2nd or 3rd day you can clean out the ear with a tissue or cotton pad.

Treat 1x per day for the next 1-2 weeks.
Treat 1x per month (or even less frequently, depending on the dog).

My pharmacist also said that the poison label resulted from EPA way out of control, probably from California. LOL!

Wayne M [last name deleted for privacy by Editor]
- Safety Harbor, Florida

Thanks, Wayne. But your posting does show how easily internet knowledge can become dangerous. You've told us of a boric acid and rubbing alcohol recipe as ear drops for pets; Dawn had heard of the recipe, didn't quite recall, and thought rubbing alcohol was appropriate for children's eyes :-(

Ted Mooney,
Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey


Just posted a response but also wanted to include this helpful link:

You can also do a Google search for "Boric Acid Yeast Infections" and you will find a lot of information about safe use of boric acid for medical purposes.

Wayne M [last name deleted for privacy by Editor]
- Safety Harbor, Florida

Boric Acid Powder
(2 lbs.)


I was searching for a boric acid eye wash recipe for my daughter's hamster. I came upon this site. Just had to post a message. My mother used to make up boric acid eye washes every time I had an eye infection (the kind on the lids & lashes--not conjunctivitis).

She would dissolve some of the powder in boiled water. I remember washing out my eye...or using a cloth that had been dipped into the still-hot water and used as a compress.

WHAT I REALLY RECALL is seeing the undissolved crystals at the bottom of the pot. The solution w/crystals never hurt my eyes. And, knowing my mother...she never used any type of formula. She always was a 'toss in what you think is OK' type person. Maybe boric acid used to be packaged with instructions in the "old days."

Judy A [last name deleted for privacy by Editor]
- Barrington, Illinois


Enough! Boric acid wash for the eye is 1/4 Tsp to 2 cups water. Boil water and add powder until dissolved. Store in an airtight and sterile container. Use an eye cup to rinse eye. Blink eye into solution so it can get under the lid.
Tried and true since Since 1952 in my family.

Jill M [last name deleted for privacy by Editor]
- Miami, Florida

Ed. note: Thanks, Jill. But if you think your "Enough!" will consolidate and terminate an internet thread, you've never tried herding cats :-)  The discussion has hardly begun! :-)


I have used boric acid for years to treat eye infections. My doctor was the person who suggested it to me. I also used it on one of my kittens who had gummy eyes, it works great! In my opinion the reason more doctors don't tell us about its benefits is because they don't get kickbacks from pharmaceutical co. if they don't prescribe expensive drugs. Knowledge is the best medicine!

Laura T
- Bronston, Kentucky


Boric acid eye wash: formula is, one level teaspoon powdered boric acid mixed into one pint of boiling water.
let cool, then use. either eye cop or sterile pad. the crystals will work as well, but take longer to fully dissolve. do not buy commercial grade borax/boric acid.
a weaker solution might be advised for youngsters. store in air tight container,use within one week for safety.

William B
- Tucson, Arizona

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