A mustard plaster, or mustard pack, is a home remedy believed to ease symptoms of respiratory conditions. It’s mainly used for coughing and congestion, but it’s also used for pain such as:

The mustard plaster remedy consists of mustard seed powder paste. The paste is wrapped in fabric and applied to the skin. It’s usually placed on the chest. It may also be applied to another body part that you’re trying to treat.

There’s no proof that mustard plasters actually work. The treatment may also cause unwanted side effects such as skin irritation and burns.

Before using a mustard plaster, it’s important to understand the potential risks.

Read on to learn how to use it, along with what safety precautions to take and other alternative treatments to try for your symptoms.

Mustard seeds have been used as medicine for thousands of years. The Greek physician Hippocrates allegedly used mustard packs to treat lung problems in ancient Greece.

According to users and proponents of mustard plasters, this remedy works by increasing circulation and warming the muscles due to the heat of mustard seeds.

Supposedly, the remedy can help relieve:

The evidence behind these benefits is lacking. To date, there isn’t solid research that proves they work, so it’s unclear if they’ll do anything for you.

Also, there’s no proof mustard plasters can help reduce symptoms of coronavirus (COVID-19).

However, sinigrin is common in plants of the Brassicaceae family, including broccoli and brussels sprouts. It’s also found in Brassica nigra seeds, or mustard seeds.

And though it’s not clear that sinigrin helps treat COVID-19, the results from a 2020 study suggest that sinigrin may be twice as helpful in treating COVID-19 as an off-label treatment as commonly used medications such as remdesivir, oseltamivir, ribavirin, lopinavir, ritonavir, and favipiravir.

These findings may help design future studies to ethically test the efficacy of sinigrin in treating COVID-19 once the condition is better understood and more scientists and researchers get involved across different disciplines.

To make a mustard plaster, you’ll need the following ingredients:

  • dry mustard powder
  • flour
  • water
  • 2 squares of fabric about 6 x 6 inches each

Here’s how to make it:

  1. In a small bowl, combine 1 tablespoon each mustard powder and flour. Mix well.
  2. Add enough water until the mixture forms a thick paste.
  3. Spread the paste onto one fabric square. Put the second square on top.
  4. Place the plaster on your chest or the affected area. Avoid areas with open cuts, wounds, or sores.
  5. Remove the plaster after 15 minutes.
  6. Wash your hands with soap and water before touching your face or eyes.

It’s critical to remove the mustard plaster after 15 minutes. If you leave it on for too long, the ingredients can irritate your skin.

If you don’t have the time or ingredients to make one, here’s where you can buy premade mustard plasters:

  • health markets
  • some pharmacies
  • online

Mustard plasters have potential risks, so use caution.

Mustard seeds contain sinigrin, a compound that gives mustard its spicy flavor. When mixed with water, sinigrin breaks down and creates allyl isothiocyanate.

A 2016 review of studies on sinigrin showed anti-cancer, antibacterial, antifungal, antioxidant, anti-inflammatory, wound healing properties, as well as biofumigation.

But information on these known biological activities is limited. Further studies still need to be conducted, and sinigrin’s molecular mechanisms also need to be explored.

When applied on the skin, allyl isothiocyanate creates a warm sensation. However, it’s also a skin irritant. If it stays on the skin for too long, it can cause:

These side effects can be severe and develop within hours after treatment. They’re also more likely to affect people who have light or sensitive skin.

There have been some reports of people developing burns after using mustard plasters.

In a 2017 case study, a woman with osteoarthritis applied mustard paste to her knee for over 24 hours and developed a second-degree burn.

In another 2017 report, a woman combined mustard powder, honey, and water to make a paste. She applied the paste to her skin and developed second-degree burns.

If you’d like to try a mustard plaster, be sure to use it properly. Never leave it on for more than 15 minutes. If you experience skin irritation, remove it immediately and talk to your doctor.

There are other options for treating the conditions mustard plasters are claimed to treat.

Here are some alternative remedies for these conditions.

Decongestant nasal sprays

If you have congestion, a decongestant nasal spray may help. This remedy works by reducing swelling in your nasal passages.

You can also try using decongestant tablets such as pseudoephedrine (Sudafed). Both products are available over-the-counter (OTC) at pharmacies and grocery stores.

Over-the-counter NSAIDs

OTC nonsteroidal anti-inflammatory drugs (NSAIDs) can help alleviate body aches and muscle cramps.

Some common NSAIDs include:

Topical pain relievers are also available in the form of:

  • creams
  • ointments
  • patches

OTC cough and cold medication

OTC cough and cold medication can help relieve symptoms due to a cold. These medications are only to be used in adults and children ages 5 years and older. Younger children should never take these medications.

Always read the ingredient label. Some OTC cold remedies shouldn’t be combined with OTC pain relievers.

Hot or cold pack

A warm compress can help relieve stiff joints and tight muscles.

Alternatively, an ice pack is useful for decreasing swelling and inflammation.

Salt water

For a sore throat or cough, gargle salt water. This remedy will also help loosen mucus.

To make a saltwater gargle, dissolve half a teaspoon of salt in 8 ounces of warm water. Gargle, then spit out.


Honey has a soothing effect on the throat, making it ideal for coughs.

Combine 2 tablespoons of honey in 8 ounces of warm water or tea. As you sip on the drink, it will thin mucus and suppress coughing.

A 2017 review found that honey effectively helped with inflammation by reducing asthma-related changes in the airways and also helped prevent asthma symptoms to begin with.

This review also found that inhaling honey could reduce the secretion of mucus by goblet cells in the airways. But further studies are needed to help improve understanding of exactly how honey helps with asthma symptoms.

Warm fluids

Drinking lots of fluids, such as hot tea or water, can help loosen mucus.

If you don’t like tea, try warm water with lemon juice and honey.

Steam inhalation

To alleviate congestion, try moisturizing the air that you breathe in.

You can use steam inhalation by:

See a doctor immediately if you have any of the following symptoms that you’re trying to treat with a mustard plaster:

Get emergency help if you have the following:

Mustard plasters are an ancient home remedy made of mustard seed powder. They’re used to treat congestion, coughing, and muscle aches, but these benefits haven’t been proven by science.

There have been reports of mustard plasters causing burns. Mustard seed powder contains skin irritants that can cause redness and nerve damage.

Use caution if you decide to try a mustard plaster. Remove the pack after 15 minutes and wash your hands after handling it.