Can you take Maalox and Benadryl at the same time? Understanding Interactions

October 12, 2025 •

4 min read

While standard drug interaction checkers report no direct interactions between Maalox and Benadryl for oral ingestion, it is still crucial to understand how they work together to ensure safe use. The combination is even used in a specific topical application, but timing considerations are essential to maintain effectiveness.

Quick Summary

This article explores the safety and considerations of combining Maalox and Benadryl. It details the active ingredients, potential effects on absorption, and explains the specific, doctor-recommended application of mixing the two for mouth sores. Proper timing and risks are also discussed.

Key Points

No direct interaction for oral ingestion: Standard drug interaction checkers do not report a major interaction between orally ingested Maalox and Benadryl, but spacing doses is advised to ensure optimal absorption.
Potential for reduced absorption: Taking Maalox and Benadryl orally at the same time may reduce the effectiveness of Benadryl, as antacids can interfere with the body's absorption of other medications.
'Magic mouthwash' combination: A recognized and safe use of combined liquid Benadryl and Maalox is as a topical treatment for mouth sores, where the Benadryl numbs and the Maalox coats the ulcer.
Timing is crucial: To avoid potential absorption issues, taking oral Benadryl first and waiting several hours before taking oral Maalox is often recommended.
Consult a professional: Always speak with a healthcare provider or pharmacist before combining medications, even over-the-counter ones, to ensure they are safe for your specific health needs.
Consider underlying conditions: People with pre-existing conditions, particularly kidney issues, should be cautious when taking aluminum-containing antacids like Maalox and should consult a doctor.

Understanding Maalox and Benadryl

To understand the safety of combining these two common over-the-counter (OTC) medications, it is helpful to first examine their individual roles. Maalox and Benadryl serve different purposes and contain distinct active ingredients, which is key to understanding their combined effects.

What is Maalox?

Maalox is an antacid medication used to treat heartburn, acid indigestion, and sour stomach. It works by neutralizing stomach acid. Its active ingredients are aluminum hydroxide and magnesium hydroxide. The magnesium component can have a laxative effect, while the aluminum can be constipating, so the combination helps to balance these effects.

What is Benadryl?

Benadryl, with the active ingredient diphenhydramine, is a first-generation antihistamine. It is used to relieve symptoms of hay fever and other allergies, including sneezing, runny nose, itchy or watery eyes, and itching of the nose or throat. A well-known side effect of Benadryl is drowsiness, and for this reason, it is also used as a sleep aid.

Oral Ingestion: Separating vs. Combining

For general, oral use to treat systemic conditions (e.g., acid indigestion and allergies), drug-interaction checkers generally find no direct, negative interactions between Maalox and Benadryl. However, taking them at the same time can still impact the effectiveness of Benadryl due to the way antacids affect medication absorption. Antacids like Maalox alter the pH of the stomach and can coat the lining of the stomach and intestines. This can interfere with how certain drugs are absorbed into the bloodstream, potentially reducing the antihistamine's effectiveness. To mitigate this, healthcare professionals often recommend separating the doses.

The "Magic Mouthwash" exception

One specific, and physician-recommended, use for the combination of liquid Benadryl and Maalox is for treating mouth sores, such as those from hand-foot-and-mouth disease or canker sores. This topical "magic mouthwash" is a different application from taking the medications orally for systemic issues. In this case, the combination works as follows:

Liquid Benadryl: Acts as a mild anesthetic and antihistamine to numb the pain and reduce inflammation in the mouth.
Maalox: Coats the mouth sores, protecting them from further irritation from food or drink.

This application is for local relief, and the goal is not for the active ingredients to be fully absorbed systemically. Patients are instructed to swish and spit, although some healthcare providers may suggest a child swallow a small amount.

Comparison of Use Cases for Maalox and Benadryl


Feature	Maalox (for oral ingestion)	Benadryl (for oral ingestion)	Maalox + Benadryl (for oral mouthwash)
Primary Purpose	Relieve heartburn and indigestion by neutralizing stomach acid.	Treat allergy symptoms like sneezing and itching.	Provide topical relief for mouth sores, reducing pain and coating ulcers.
Mechanism	Active ingredients (aluminum and magnesium hydroxide) neutralize acid.	Active ingredient (diphenhydramine) blocks histamine receptors.	Combined actions: Diphenhydramine provides local anesthetic effects, and Maalox coats the sores for protection.
Risk of Interaction	Low risk for systemic drug interaction with Benadryl.	Low risk for systemic drug interaction with Maalox.	Specifically designed and recommended combination for topical use.
Timing for Use	Can be taken as needed, but for oral ingestion, it is best separated from Benadryl.	Can be taken as directed for allergy relief.	Swish and spit as directed, especially before eating.
Safety Considerations	Possible side effects include constipation or diarrhea, depending on the specific formula.	Can cause significant drowsiness; avoid driving or operating machinery.	Swallowing the mixture may be advised for children, but follow a healthcare provider's instructions carefully.

Key Safety Considerations and Best Practices

Timing is important for absorption: If you need to take both medications for systemic issues, such as indigestion and allergies, space them out. Taking Benadryl first and waiting several hours before taking Maalox may help minimize any potential interference with absorption.
Understand the purpose: The combined use for mouth sores is distinct from oral ingestion for internal conditions. Do not confuse these two applications. The mouthwash is for local relief, not for treating systemic symptoms of allergy or indigestion.
Potential side effects: Benadryl is known for causing drowsiness, which can be a significant side effect. Maalox can cause changes in bowel movements. Be aware of these effects when taking either medication.
Special populations: People with underlying health conditions, particularly kidney issues, should be cautious with aluminum-containing antacids. The kidneys are responsible for eliminating aluminum from the body. Individuals with impaired kidney function may be at risk for aluminum buildup, so consult a doctor before use.
Consult a professional: Always speak with a healthcare provider or pharmacist before combining any medications, even over-the-counter ones. They can provide personalized guidance based on your medical history and other medications you may be taking.

Conclusion

While there is no major drug interaction that prevents you from taking Maalox and Benadryl together, the way you use them matters significantly. For treating separate conditions like indigestion and allergies, it is best to space out the oral doses to ensure Benadryl is absorbed effectively. However, for a specific topical application for mouth sores, mixing the liquid forms is a recognized and safe remedy, often referred to as a "magic mouthwash." In all cases, consulting a healthcare professional is the best way to ensure safety and effectiveness.

Authority Link

For more detailed information on drug interactions, the official Drugs.com website provides a comprehensive interaction checker tool.

Frequently Asked Questions

Yes, mixing equal parts of liquid Benadryl and Maalox to create a 'magic mouthwash' is a common, medically-accepted practice for soothing mouth sores and canker sores. You should swish and spit this mixture, although a healthcare provider may give specific instructions for children.

For optimal absorption, it is best to separate the oral intake of these medications. Taking Benadryl first and waiting several hours before taking Maalox may help prevent the antacid from potentially interfering with the absorption of the antihistamine.

You should generally not take them simultaneously if both are for oral ingestion. Maalox (an antacid) could reduce the effectiveness of Benadryl (an antihistamine). Separate the doses by a few hours to ensure each medication works as intended.

While there is no major contraindication, taking them at the same time for systemic issues may lead to a reduced absorption and effectiveness of Benadryl. This is why staggering the doses is recommended.

If you accidentally take them at the same time, it is unlikely to cause a serious reaction, but Benadryl may be less effective. If you have concerns or experience any unusual symptoms, contact your healthcare provider or pharmacist for advice.

Benadryl can cause drowsiness, so avoid driving or operating heavy machinery until you know how it affects you. Maalox can cause changes in bowel movements, with magnesium often causing a laxative effect and aluminum causing constipation. Combining them in the liquid form for mouth sores does not carry the same systemic side effect risks.

Individuals with kidney impairment or kidney disease should be cautious with aluminum-containing antacids like Maalox, as it can lead to aluminum buildup. Always consult a healthcare professional before combining any medications, especially with underlying health conditions.