Dear Outdoor Joe®, Does Heat Make Rhus Tox Go Bad?

Posted on February 10, 2021 at 4:30 PM by Tom Swegle

A photo inside a car with the sun shining in, and Outdoor Joe is standing outside the car pointing up to the sun

Over-the-counter medicines expire and must be properly disposed of… Did you know temperature can be a problem, too?

Every month we receive tons of letters, emails, and messages via carrier pigeon about the various fears related to poison ivy. Outdoor Joe® is here for you! Although Joe is a poison ivy pro, sometimes he likes to refer to the experts for a closer look and deeper analysis.

This month, Joe and experts from the Food and Drug Administration (FDA) share the dangers of keeping over-the-counter (OTC) medications that have been exposed to extreme temperatures after receiving a letter from an Outdoor Joe® fan, Madison.


Dear Outdoor Joe®,


My mother purchased Rhus Tox for me over the summer, which she sent home with me when I visited her in June. I tossed it in my purse and forgot it was there until a week or so later. My purse sat out in my car in the summer heat for a handful of days while I was at work, with the bottle of unopened Rhus Tox in it.
Since then, it's been stored in my medicine cabinet in my bathroom. Unopened. It recommends starting the dose in February, so that's why I've waited until now to reach out.

Would the heat have damaged the product or is it okay and would still be effective?
I look forward to hearing from you.




We’re glad you asked, Madison! Unfortunately, the storage of OTC medicines is often overlooked, but a very important part of safe drug use. Too many people are unaware of potential dangers from improper storage of OTC medicines, especially when it comes to extreme temperatures that meds have been exposed to! Luckily, your friend Joe has compiled some great information to help clarify the why’s and hows of proper medicinal storage.

Over-The-Counter Medicines And Extreme Temperatures 

Most likely, you’ve found yourself in a position similar to Madison’s - accidentally forgetting about a bottle of medicine and leaving it in a hot car or forgetting about it over winter. What you do with the medicine once you discover it will depend on the safe storage instructions for that particular med.

If you’re still unsure, the safest thing to do is to discontinue the use of that medicine and replace it with a fresh supply. Although it’s generally unlikely that medicine will become harmful from heat, cold, or moisture, they may become less effective if exposed to extreme conditions.

1. Why is it important to keep your medicines from getting too hot or too cold?

Most OTC medications have been designed to be stored at room temperature (68-77 degrees Fahrenheit), no extreme heat, and no extreme cold; in an average air moisture level (relative humidity of 35-45%); and in their original packaging. As long as these conditions are met, the active ingredients in the medication will remain effective until the expiration date shown on the packaging.

The Food and Drug Administration (FDA) holds OTC manufacturers, such as Outdoor Joe’s, to high safety and quality standards. 

Products must be tested extensively to show stability, including under extreme environmental conditions, and to scientifically prove they’re able to retain the original properties when kept under the conditions listed on their Drug Facts label throughout their shelf life.

2. What sort of quality testing is required by the FDA for OTC medications?

The FDA requires OTC manufacturers to test samples of their product(s) for the duration of the product’s shelf life. Part of that testing process includes putting products through “stress testing.” If a product is going to be considered safe and reliable, it must pass with flying colors!

Each product during testing will be exposed to things like temperatures, light conditions, and moisture levels that are outside of the recommended storage conditions. During the testing, samples are taken at regular intervals to evaluate the drug. If any concerns arise regarding the drug’s safety under these conditions, it’s further evaluated.

Bottom line - an OTC product must be safe in order to be effective when it’s stored in its ideal conditions.

3. How can I keep my OTC medicines stored safely at home?

It’s really important to understand that OTC products are packaged the way they are in order to keep them as stable as tested. By removing the product from its original package, it becomes more susceptible to environmental changes, and then may break down or become less effective. So, if possible, always keep OTC’s in their original packaging.

Additionally, once you buy an over the counter medication, examine its Drug Facts label. There you should be able to find its safe storage instructions. It may note if should be stored at room temp, if it needs to be kept out of the light, or away from moisture. Additionally, you definitely need to make sure medicine is stored away from young children.

4. How do I keep my medicines from being exposed to extreme temperatures and conditions when I’m traveling?

Air Travel

Traveling is great! Flying can be stressful, and you never know what may happen. So the best thing to do for both the medication itself as well as any potential traveling issues you may run into is to carry medicine onto the plane. The cabin will be climate-controlled, allowing you to follow optimal OTC safe practices.

Car Travel

If you’ve ridden in a car (hello, everyone!), you know it’s easy for a vehicle to become pretty toasty or extremely cold, even when it’s not just sitting in a parking lot! So, it’s rarely if ever a good idea to leave medicine in a car, even for short periods of time.

If you’re traveling, don’t put medicine in the trunk, and don’t leave them overnight. If you happen to forget, remember… it’s recommended to discontinue the use of that medicine and replace it with a fresh supply.

Mailing Your Meds

Did you know that medicine gets shipped? Oftentimes it’s a pharmacy sending something across the country, and they use climate-controlled transportation methods to ensure that OTC products are not exposed to extreme conditions.

The same may not be necessarily true for every day delivery services such as the US Postal Service, UPS, and FedEx. So if you must ship medicines through a mail service, you have to know your package may be sitting for an extended period of time and exposed to very hot temperatures during the summer, and very cold temps throughout winter. 

Be Safe, Not Sorry

Like we said, how OTC medicines are stored often gets overlooked, but it’s a really important part of safe drug use. Make sure to examine the Drug Facts label on any product for guidance on how to best keep it. And remember, even if a drug has been well-tested, packaged correctly, and stored as directed, it doesn’t necessarily make it immune to extreme changes in temperature and moisture.

If you have any questions about the safety and effectiveness of a product, I’d like to suggest you go with the line, “When in doubt, throw it out!” Purchasing a brand new package of OTC medicine not only offers safety and efficacy assurances but peace of mind.

We hope this helps answers some of your questions about the combination of extreme temperatures and medication! 

With Love,

Outdoor Joe®

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