How Strong Is the Evidence for Herbs for Respiratory Tract Infections?

Respiratory tract infections are common reasons for being prescribed drugs. But the widespread and often inappropriate use of drugs is contributing to resistant microorganisms, resulting in harder to treat illnesses that last longer. Herbs offer an exciting solution. But how strong is the evidence that they work?

This just-published review set out to examine the level of evidence for several herbs commonly used for respiratory tract infections.

It looked at studies of different sorts on different formulations of the herbs. Upper respiratory tract infections include illnesses like the common cold, sinusitis, tonsillopharyngitis, adenoiditis and laryngitis; lower respiratory tract infections include more serious illnesses like bronchitis and pneumonia.

Of the studies included, 66 were randomized, placebo-controlled studies.

Echinacea is one of the most popular, best studied herbs for respiratory tract infections. The review included 19 randomized controlled studies, demonstrating “strong scientific rigour.” Overall, they rated the evidence level for echinacea as “high to moderate evidence, supported mainly by randomized and controlled” studies.

Andrographis is a readily available herb that is remarkably fast and effective herb for fighting respiratory infections. The review identified 22 randomized controlled studies that demonstrated “high to moderate evidence level.”

Several studies have shown ivy to be an effective expectorant herb that is effective against coughs and bronchitis. It has even proven to be as potent as the drug ambroxyl for tough bronchitis. The review says “numerous clinical trials have demonstrated the efficacy of H. helix [ivy] in alleviating symptoms of acute and chronic RTIs by reducing coughing, bronchospasms, and secretion.” But it concludes that the evidence is not yet “definitive.”

Thyme has an “established role” in managing respiratory tract infections, “particularly acute bronchitis.” It is an antimicrobial herb used as an expectorant and for cough and bronchial spasm. The review found 3 randomized controlled studies and 2 non-randomized controlled studies and evaluated the level of evidence as “moderate.”

Marshmallow is a traditional herb commonly used for mucous membrane irritation, including sore throat and cough. The review found “a small but significant number of clinical trials,” including 3 randomized controlled studies, and evaluated the level of evidence as “moderate.”

Elderberry is a powerhouse herb for respiratory infections. The review included several double-blind, placebo-controlled studies that “demonstrated a high to moderate level of evidence.”

Ginger is a powerful and versatile herb that can help respiratory symptoms, including “headaches, colds, nausea, and vomiting” as well as “throat irritation, coughing, nasal congestion and sneezing” as well as “inflammation and breathing difficulties,” including COPD. The review identified 9 randomized controlled studies and concluded that they all demonstrated that ginger “can significantly impact RTIs, yielding evidence that ranges from moderate to strong.”

One of the most powerful and versatile herbs in the world, turmeric/curcumin is many things, including anti-inflammatory, antioxidant and antimicrobial. It is both antibacterial and antiviral. The review concludes that all of turmeric’s properties and all the studies “support the fact that it can be used successfully in both acute and chronic respiratory conditions.” All the studies were randomized controlled studies, “ensuring the highest standard of evidence.”

Herbs for respiratory tract infections are well studied with “robust evidence” being found for echinacea, andrographis, elderberry, ginger and turmeric.

Nutrients. 2026 May 12;18(10):1534.

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For much more on preventing and treating respiratory infections, see our book The Family Naturopathic Encyclopedia.

For much more on these respiratory herbs and more, see our book Healthy Herbs: Your Everyday Guide to Medicinal Herbs and Their Use.

For comprehensive natural help with your health, including respiratory health, make an appointment to see Linda Woolven now. Linda’s clinic is now open for in person and virtual appointments.

The Natural Path is intended for educational purposes only and is in no way intended for self-diagnosis or self-treatment. For health problems, consult a qualified health practitioner for a comprehensive program.

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