Penicillin Allergy – Things You Need to Know

Illustration of various colourful pills, with text overlay reading "Allergic to penicillin? Things you need to know."

What is penicillin?

Penicillin is one of the first antibiotics discovered, and has been used for nearly 80 years to treat common bacterial infections such as bronchitis and laryngitis. It is inexpensive and can treat skin, ear, sinus and upper respiratory tract infections.

Penicillin is one of the safer antibiotics

Compared to other antibiotics, penicillin can be more effective and less likely to result in antibiotic-resistant bacteria. It also has a lower risk of causing C. difficile infection, a severe and hard to treat diarrhea.

Do you have a penicillin allergy?

You may have had a reaction when taking penicillin in the past in the form of hives, itchiness, rashes or swelling. These are common side effects and do not necessarily indicate an allergy. Fewer than 5 in 10,000 people have a true penicillin allergy.

In fact, 80 per cent of adverse effects related to penicillin disappear over time. This means that you may be able to take penicillin safely again the next time you need it, even if you have had reactions to the antibiotic in the past.

Should you take penicillin? 

Always share any past penicillin reactions with your health-care provider. They will let you know if you should try penicillin again or use another antibiotic. While your health-care provider may avoid prescribing you penicillin, they may also determine that it is safe to try again.

This is important as the alternatives to penicillin are often stronger antibiotics which may have a higher risk of side effects and should be saved for times when they are truly needed. If these alternative antibiotics are used too much, bacteria may develop resistance to these drugs, and they may not work in future.

Penicillin allergy and what you can do

Before asking to be prescribed a different antibiotic, talk to your health-care provider. They will be able to evaluate your allergy or refer you to an allergist.


Allergic to Penicillin? Brochure

Download the brochure to learn about penicillin allergy, and how to be Antibiotic Wise.

Allergic to Penicillin? Poster

Download and use the poster to raise awareness about penicillin allergy.

Penicillin Allergy Fact Sheet

Did you know that half of all penicillin allergies go away within 5 years? Learn more about why penicillin may still be the right choice even if you have been told you have an allergy.

BC Women’s Penicillin Allergy Challenge Test

Fact sheet for a new initiative from the BC Women’s Hospital testing penicillin allergies of pregnant women.

Drop the Label Website

Patient and provider information on antibiotic allergies.

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