Can you use expired Erythromycin? 

Can you use expired Erythromycin? 

It is not recommended to use expired Erythromycin or any other medication for that matter. The Food and Drug Administration (FDA) has clearly stated that expired medications have no guarantee regarding their safety and efficacy, and Erythromycin is no exception (1). 

Even if Erythromycin doesn’t become toxic, it does lose its efficacy after the expiry date. Such an ineffective antibiotic can lead to a number of problems. 

What are the possible dangers associated with the use of expired Erythromycin? 

A few unfavourable possibilities for using expired Erythromycin include:

Therapeutic failure 

One of the major concerns when it comes to using expired Erythromycin is therapeutic failure. An active infection needs a fully potent antibiotic to disrupt its growth. 

When you use an expired antibiotic, the bacteria continue to thrive and you don’t find any relief in your symptoms whatsoever. 


Another possibility of using expired Erythromycin is antibiotic resistance. This means that the infection-causing bacteria learn to adapt to the presence of Erythromycin as the expired antibiotic is not strong enough to kill them. 

This resistance remains a problem even if you start using an unexpired Erythromycin. 

Worsening of infection 

Another important concern is the worsening of the infection. If the antibiotic does not work, the bacteria continue to multiply and your symptoms may start to become much more intense. 

Bacterial infections should never be left untreated as a heavy bacterial growth can spread to your bloodstream and increase the risk of septicemia (Blood infection). 

Furthermore, Erythromycin is also available as ophthalmic ointment which also expires – way earlier than Erythromycin tablets. Using expired eye ointment/drops can be more dangerous as it can exacerbate your eye infection and may cause permanent ocular damage.

What to do if you have taken expired Erythromycin? 

If you have taken a dose or two of expired Erythromycin, don’t worry. However, I’d recommend not taking it any further. Erythromycin is a prescription antibiotic. If you think you have an infection or a relapse of an infection you previously had, talk to your doctor. 

You may benefit more from another antibiotic and even if Erythromycin is the choice of drug for you, an expired one will do you no good. This is why it’s best to consult your healthcare provider and get a new prescription. 

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U.S. Food and Drug Administration. Don’t Be Tempted to Use Expired Medicines [Internet]. Silver Spring (MD): U.S. Food and Drug Administration; 2021 [cited 2022 Oct 26]. Available from: