While it may not be harmful to take expired amoxicillin for a tooth infection, it does lose its potency and effectiveness in fighting abscesses. For that reason alone, we wholly recommend against taking this antibiotic if you truly have an infection in your mouth.

We will explain in further detail as to why it is a bad idea to take this expired antibiotic and what can go wrong if you try taking more of it. You know that there is a much better alternative right?
Consequences of taking expired amoxicillin
You probably won’t get sick from taking expired amoxicillin but you also won’t get the effect that you’re looking for.
- It begins to lose potency once it’s past the expiry date.
- It could also trigger antibiotic resistance from the bacteria which can be dangerous.
For the record, no you shouldn’t try to take more of it to compensate for the decreasing potency because it can be harmful.
Decreased potency
Since this antibiotic loses its potency and effectiveness once it expires, it will most likely be an insufficient dose to fight the abscess in your mouth. That means taking it won’t do very much for you.
Below are some research data from a study which compared the amount of bacteria for a non-expired amoxicillin vs an expired one.
Amoxicillin concentration (mg) | # of bacteria from non-expired amoxicillin | # of bacteria from expired amoxicillin |
---|---|---|
5 | 73.666 | 138.666 |
10 | 104.66 | 125 |
15 | 86 | 102.333 |
20 | 92.333 | 90.666 |
25 | 86.333 | 109.666 |
30 | 69.333 | 84.333 |
35 | 46.666 | 111.666 |
For the most part, the unexpired amoxicillin had much more incidences of less bacteria than the expired experimental group. In the 35mg concentration of antibiotics, there were nearly 3x as many bacteria present in the expired medication.
What we’re trying to say is that your infection most likely won’t go away by taking this medication. It will not give you the effect that you’re looking for.
Antibiotic resistance
There is a risk of developing antibiotic resistant bacteria if you take amoxicillin that has already expired.
How that happens: Since the antibiotic is no longer as potent, it means that the bacteria which is causing your tooth infection can survive it and acquire resistance to it.
What it means for you: If the bacteria develop a resistance to the antibiotic, it means when you finally decide to see the dentist and they prescribe you unexpired amoxicillin, it may not work. Typically antibiotic resistant strains of bacteria will need to be treated at a hospital.
Ultimately, this may end up being a lot more complicated and costly for you by inadvertently taking this medication beyond its best by date.
What if I just take more of it?
Please do not try to take extra doses of amoxicillin while thinking that you can make up for its decrease in potency by taking more. It is very dangerous to be taking expired medication because you don’t know what the effective dose is.
You can very easily overdose on this medication because you don’t know how much you’re actually taking. That in itself is unsafe and can potentially be extremely hazardous to your health so we recommend against a macgyver solution.
Should I take expired amoxicillin?
You should not be taking expired amoxicillin because you shouldn’t have any of it in the first place. According to MedlinePlus, all unused amoxicillin should be disposed of within 14 days.
That means if you didn’t finish taking it or you had some of the antibiotic left over, you should’ve gotten rid of it within 2 weeks. There are proper medication disposal procedures by the FDA if you visit their site.
They recommend bringing the amoxicillin that is expired to a Drug Take Back Location.
When does it expire?
All medications expire and antibiotics are no different. On average, amoxicillin should expire within 1-2 years of their manufacture date.
Signs that it may have expired:
- Expiration label. The most obvious sign is to check the label for the expiration date. All of them should be dated as it is a part of FDA regulations. Just like how foods have an expiration date on their label, medications are of no exception.
- Pills look distorted. If the pills look damaged or distorted in anyway, you should consider them to be unfit for consumption. If they were stored in a heated or humid place, sometimes the outer layer of the capsule can melt.


If you don’t see an expiration date for whatever reason… you should assume that it is expired. Sometimes people will move medications from one bottle to another and that may be why it isn’t there.
Better alternative
A safer and more effective alternative to taking expired amoxicillin if you have a tooth infection is to just see your dentist. If your tooth is indeed infected, they will happily give you a prescription for a fresh batch of amoxicillin that isn’t past its due date.
However, we’re not trying to rain on your parade but there are very few types of oral infections that will go away simply by taking antibiotics. Most of these conditions require some type of dental treatment such as an extraction, root canal, or even draining a swollen abscess. It all depends on what is causing the infection.
Do you even know why and how it got infected in the first place?
You probably don’t which is why we highly recommend seeing your dentist for a consultation so that you can get a diagnosis and get proper treatment. That is the only way to permanently eliminate a dental abscess.