Onion acts as an expectorant and mucolytic, helping to loosen and expel phlegm.

onions are traditionally believed to help with cough and congestion, and there’s some scientific basis for that idea.

🧅 How Onion May Help

• Expectorant effect (loosens phlegm):
  Onions contain sulfur compounds (like cysteine sulfoxides) that may help thin mucus, making it easier to cough up.

• Mucolytic action (breaks down mucus):
  Certain compounds in onions may reduce mucus thickness, similar in principle (though much milder) to medications like acetylcysteine.

• Anti-inflammatory properties:
  Onions contain quercetin, an antioxidant that may help reduce airway inflammation.

• Mild antimicrobial effects:
  Some onion compounds have antibacterial activity, which may support immune response.

Common Home Remedy

A popular traditional remedy is:

• Slice an onion

• Add honey

• Let sit for several hours

• Take 1–2 teaspoons of the syrup as needed for cough

(Honey itself is well-supported for soothing coughs.)

Important Note

Onions are not a replacement for medical treatment, especially for:

• Persistent cough (longer than 3 weeks)

• High fever

• Shortness of breath

• Wheezing

• Children under 1 year (no honey)