Extreme ingestion of menthol can result in an overdose. Cough drops contain small amounts of menthol, meaning it is extremely unlikely a person can ingest enough to reach this threshold.

These candy-like lozenges can feel soothing and help calm a cough, at least temporarily. And if the symptoms are particularly severe, some people may eat a lot of cough drops.

Although it is difficult to overdose on them, there are some things to consider before using cough drops or consuming excessive amounts.

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Menthol is a compound of peppermint, eucalyptus, and other mint oils. It is common in cough medications and can provide a cooling, or soothing effect. Many cough drops pair menthol with mild local anesthetics.

Cough drops usually have 5–10 milligrams (mg) of menthol per drop. Ingestion of pure menthol can be dangerous, but the small quantities in cough drops make overdose from their consumption highly unlikely.

People should treat cough drops as they do any medication, by following the information on the label to find out the safe dosage.

People who take other medications or who have other health conditions should also ask a doctor before taking cough drops or any new medications.

Fatal dose

It may take up to 1,000 mg of menthol per kilogram (kg) of body weight for a lethal dose. A person would also need to ingest a high level of menthol in a short time to risk toxic effects. It is unlikely a person will be able to reach this threshold by eating cough drops.

Doctors report only one recent instance of fatal peppermint oil poisoning, but it was not from cough drops.

A 21-year-old died after inhaling high amounts of peppermint fumes containing menthol and other components. The cause was entering a peppermint oil tank to clean it.

There was no evidence of consuming peppermint or menthol but only the toxic effects of breathing unusually high amounts of peppermint fumes.

How many cough drops are too many?

There is no standard limit to how many cough drops a person can consume. This is because the amount of menthol and other ingredients vary between brands.

If a dose of 1,000 mg/kg is necessary for overdose, then a 70-kilogram (154-pound) person would need to consume around 7,000 cough drops containing 10 mg of menthol each for a fatal dose.

Menthol is considered to be safe, and cases of poisoning are extremely rare.

A study published in Case Reports in Medicine describes an 86-year-old man who was unconscious and taken to the emergency room. After regaining consciousness, doctors determined the person was experiencing:

  • heartburn
  • diarrhea
  • dizziness
  • sores in the mouth
  • skin lesions with a dry, yellow crust
  • muscle weakness
  • decreased kidney function
  • problems of thinking and mental function

Doctors ascertained that the cause was eating 2 bags of menthol-rich cough drops daily for 20 years. Most of the symptoms went away after the individual stopped eating the cough drops and had physical therapy.

One report found that inhaling concentrated peppermint fumes can cause unconsciousness, a coma, and seizures. Death occurred after 10 days of hospitalization.

Menthol can cause allergic reactions and is unsafe for topical use on the faces of younger children. However, there are limited instances of menthol allergic reactions in medical literature.

Menthol can be an irritant for people with sensitive skin. People should stop using cough drops and consult a doctor if itching, burning, or swelling occurs after eating them.

Some cough drops contain as much sugar as candy. This sugar level may not be safe for people with blood sugar problems and diabetes.

Visit our dedicated diabetes hub here.

Some lozenges can contain other vitamins and minerals, such as zinc and vitamin C.

As with any product containing supplementary vitamins and minerals, people should not take them in excess amounts without a doctor’s approval.

People should read the cough drop label before taking them to know what they are ingesting.

Cough drops may provide relief for a cold or allergies. They will not treat the underlying health problem, however.

Sometimes, a cough or a sore throat is a sign of a more serious health issue. People should see a doctor if symptoms last more than a few days or worsen. A severe cough, constant coughing, or a cough that produces blood or green or yellow mucus requires emergency assistance.