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 (4) | 9% |
Keny (Canada) on 09/19/2020: 
Why it works: It seals the wound.
It essentially dries the wound and causes it to contract, sealing the wound. You have to let it dry for it to be effective, this usually takes 2-3 minutes, but I'd give it more time to be sure (depends on your air).
It only hurts for the first 20-30 seconds, unlike other methods, and it seems to hurt less than salt/baking soda. It doesn't hurt long because the wound ends up sealed, so nothing that doesn't penetrate the seal will then hurt it!
If you use it while it is still SMALL it will hurt a lot less. I highly suggest using it when you see even the remote possibility of a canker sore. Let it dry, then rinse your mouth. Don't drink the alum, unless you're genetically allergic it probably won't kill you, but it's probably not good for you either.
The havoc of having an open wound in your mouth letting in all sorts of toxins and bacteria is likely way worse than any effect you can get from slight contact with alum, which is used as a pickling ingredient. The exception is if you're deadly allergic to alum. You can test by putting pin pricking your skin very lightly with a sterilized needle and putting a little alum to see how you react to it (that is how allergies are tested).
Miss T (NC ) on 08/31/2019:
Lauren (Ny) on 02/22/2018: 
Stacy (New Haven, Ct) on 07/21/2017:
Is there ANYTHING worse than trying to chew on one side of your mouth to avoid irritating a canker sore? Anything worse than avoiding your favorite foods/drinks as to not make the pain worse?? I love salty snacks, love my coffee and salt & vinegar chips, so I'm definitely prone to cankers sores every couple months.
My method is as follows:
Dip the end of a Q-tip into a bit of raw honey, just enough to coat the tip. Then dip the honey end into the alum. For this next part, I find it best to use one hand to hold my iPhone with the flashlight on to light up the inside of my mouth so I can see what I'm doing. With the other hand, place the Q-tip on the canker sore to coat it. Don't swallow for 1 minute. I do this in front of the bathroom sink because sometimes you do drool! Then I rinse my mouth with water, go to sleep, and by the morning it's painless and much smaller, if not completely gone.
Sometimes the after taste of the alum can leave your mouth feeling funny and dry, but drinking water definitely helps.
Thanks to to all who have suggested this amazing remedy! My mouth thanks you! :)
Twinkytoze (Brampton On) on 06/18/2017:
Patricia (Bucyrus, Mo) on 07/26/2016:
Josh (Weatherford) on 07/05/2015:
I set a timer on my phone for 2 minutes at first (I did this process twice for each sore), I never got to the point where I was on the verge of tears. My face got a little tingly, that was really it. But it's 10 minutes that I'm typing this after I went through this, and it still quite burns. But I'm only assuming that will go away within the next half hour(or maybe I missed a little tiny sore). After the first sore was taken care of, I got a large glob of it, and stuck it right in the center of alllllll of the sores. Yup. It hurt. But remember this when I say, you will never be able to get rid of a canker sore without pain, unless anesthesia is involved. I then set a timer for 2 and a half minutes, and waited it out. The sores definitely feel a little bit different when I touch around them with my tongue. They didn't burn AT ALL right when I rinsed with water, but only started burning again about a minute after. So that must be the side effects of the powder settling in deep in the sore. Which I also assume is a good thing? Kill that sore, alum. Kill it.
If you have any questions, feel free to ask away. I plan on doing this again tomorrow morning if the pain is still there (which I assume it will be, knowing my luck). So far, alum works!
Joecool025 (Sacramento, California) on 03/24/2015:
Bought a 2 ounce jar from the local grocer for about $5, which is more than enough. I bet 1/4 ounce would be plenty.
Over the bathroom sink, wet a q-tip, and dip it in the alum powder, roll it around to get a good amount on it. Then locate your canker sore and press and hold it on there real well. Time out 2 1/2 minutes on your watch or phone, then wet the other side of the q-tip, reapply, and repeat for another 2 1/2 minutes. Afterwards, rinse out that side of the mouth really well.
This stuff stings, and tastes bad. Try not to taste it with your tongue, and try not to swallow, just let the drool come out of your mouth down into the sink. It's not the most pleasant 5 minutes I've ever spent, but it really helped attack the sore, and minimized it, and dropped the pain down to about a 1 or 0 in 2 days.
I did this process twice a day for 2 days, and I am canker sore free!
Andrea (Des Moines, Ia) on 01/29/2015:
Cb (Ny, US) on 10/23/2014:
Buy some Alum (a pickling agent, should be able to find it in the spice aisle) and some mouth wash (I don't think it matters but I used a antiseptic tartar control one). Using your finger or a cotton swab dab some (not much, maybe a pinch) of alum onto the muceole and leave it alone as long as you can keeping the area dry by holding your lip (or wherever) out of the wetness of your mouth. I did for a about 20 mins - then wash it out carefully. WARNING - alum does not taste good and will feel strange in your mouth. Then use the mouth wash. The alum should "dry up" the muceole and the mouth wash will keep it from getting infected or bigger.
The next day (I did the first time at night) I noticed where I had placed the alum had dried the skin, much of my mouth was dry with peeling skin (not as bad as it sounds). I repeated this process three times within a six hour period the day after I started the remedy. I recommend starting on a weekend so you have time to do this. At this point I could see the white spot within the muceole (salivary gland) which is a good sign. After that I used mouth wash consistently for three days and my muceole healed and completely went away. It's now been a month without it coming back. Hope this helps someone out there!
Edward (San Francisco, CA) on 09/05/2014:
Katherine (Calgary, Alberta) on 06/24/2012:
Cb (San Diego, CA) on 05/26/2012:
Selia (Ocala, Fl) on 05/21/2012:
Kb (Monterey, Ca) on 05/01/2012:
Farooq (Cornwall, Ontario, canada) on 02/06/2012:
But then I read about sodium lauryl sulfate found in most of toothpastes was one of the reason for Cankers. I stopped using those toothpastes and thank God I do not get it very often, as I was use to get it about twice a month.
But once in a while I will get it. This time it was on my tongue I read it on this website about Alum and bought it from Food basics. Used it once and seems to be very helpful.
Jessica (Waconia, Minnesota) on 01/26/2012:
Dreamer (Salinas, Ca) on 01/26/2012:
John (Lake Oswego, Oregon) on 01/19/2012:
Mariana (Roseville, Minnesota) on 12/22/2011:
Anyhow, what we do to treat a cankersore is merely moisten a Q-tip, and dip it in a very small amount of alum mixed with a teaspoon of warm water. After the alum is on for a few minutes, just rinse your mouth because the alum is very bitter. People also use alum as a mouthwash and to treat gum disease or aching teeth. It's used to treat eczema itching, and styes as well. I'm sure the solution would need to be much milder for use on the eyes, or as a mouthwash, or in treating eczema. Anyway, I hope others might want to mention their experiences with using this common household ingredient. Mariana
Sfcb1 (San Francisco, Ca Usa) on 12/02/2011: 
Jennifer (Midland, Michigan) on 09/15/2011:
Lyn (Springfield, Vermont) on 08/31/2011:
I have been reading this site and decided that the alum couldn't hurt anymore then the acid from my spaghetti had.. So I got brave and wet my finger and held it on the sore under my tongue.. It burned wicked bad.. I thought ya right this is going to work.. Still hurting and throbbing I tried the aspirin.. Held it to the sore till it disolved and didn't rinse my mouth.. Still just letting it disolve and swollowing as needed till the aspirin is gone..
Its amazing after doing this the pain had gone.. I can't believe it.. Will report back tomorrow and see how it is then.. All I can say is its worth a try.. It seems to have worked for me so far.. Good luck..
Mikayla (Toronto, On, Canada) on 08/26/2011:
I never get canker sores, but a few days ago, I got itchy red hives on my torso as well as 6 canker sores under my tongue and my cheeks. I've had several surgeries but have never been in such pain in my life! So bizarre that such a little thing can cause so much discomfort.
Anyway, after reading the comments, I tried Alum and so far it's amazing. It has really numbed the canker sores. I can eat!!
My only caution is because it does numb so well, be aware not to bite your cheek accidently. I did that and another canker sore developed; but the overall relief is so worth it.
Daisy (San Francisco, Ca) on 08/05/2011:
I had a canker sore on my tongue for three days that was hurting so much, I couldn't eat or talk. I stumbled upon this thread in my google search for remedies and this was the first time I'd ever heard of alum.
I went to the grocery store, picked some up (in the spice aisle) and went straight home. I dipped a wet Q-tip in the alum and applied it directly to the sore on my tongue. Yes, it stung, but not horrendously (and certainly not as bad as fingernail polish remover --- cannot believe I admitted I did that). There was some drool and whatnot, and fifteen minute later my tongue was throbbing.
I dissolved an asprin directly onto my tongue and SERIOUSLY? THE PAIN ALMOST COMPLETELY WENT AWAY.
I woke up this morning and while the sore is still there, and even bigger, IT DOESN'T HURT.
After dealing with intensely painful canker sores for almost 30 years, I cannot even begin to tell you how happy this makes me. I feel like alum is going to change my life for the better. I know this sounds ridiculous, but one bad canker sore can seriously ruin your week.
THANK YOU EVERYONE!
Kimkat (Hingham, Ma) on 04/27/2011: 
Better But With Side Effects
I might have to call my doctor for painkillers - this is almost unbearable (yes I have a low threshhold for pain)
Bg (Lakewood, Oh) on 02/19/2011:
I used to use a prescription paste which I haven't been able to get out here (Kenalog in Orabase? I think) which worked wonders and would quite literally get rid of my sores overnight. Since I've been unable to get that prescription filled, I needed a different remedy, so I went with alum. My only quip with alum is that it tastes NAAAAASTY. Seriously, if you swallow it, you will probably vomit. Bitter, awful, disgusting taste--BUT it works like a dream on canker sores and dries them out after a few applications. I usually daub a bit on the sore with a wet Q-tip, then let it sit there and dry for about five minutes before rinsing out my mouth and/or brushing my teeth (because the taste just sticks to your tongue). The more stubborn sores still take a few days to go away, but the alum seems to alleviate the pain and bring down the swelling and the size of the sore almost immediately. I highly recommend this remedy -- just remember not to swallow or spit it out before your five minutes are up.
Pcheeks (Washington, Dc, Usa) on 06/01/2010:
Michael (Oklahoma City, Oklahoma) on 05/11/2010:
Dave (Austin, Tx) on 11/30/2009:
Thought I might help those of you who are suffering with cold sores etc. As a child I 'suffered' with this malady on occassion. When ever it happened, I would tell my mom and she would immediately reach into the kitchen spices for the alum. This is the new information which I have not seen on any site thus far. Before using the alum mom would put a small amount on a disposable piece of metal (usually the top removed from a can of vegetables) and heat the alum to the point where all the moisture is driven from the alum powder. At this point the alum will crystallize on the can lid (This is what I learned to call burnt alum). Allow to cool. Once the crystallized alum has cooled, take a spoon and crush the burnt alum and apply as described elsewhere. As mentioned alum is an astringent, and the value of this process is to improve the astingent properties of the alum. As with those who have used this remedy regularly, I also had complete relief within two days.
