No evidence supports the use of medicinal plants mullein and marshmallow to cure or mitigate COVID-19
Medicinal herbs can be effective in treating some diseases or alleviating their symptoms. However, no clinical data so far has shown that mullein leaves or marshmallow roots are effective at treating or mitigating COVID-19.
Inadequate support: There is no published scientific evidence showing that the mullein leaves and marshmallow roots can cure COVID-19 or alleviate its symptoms.
Many claims of alternative or natural remedies against COVID-19 circulated on the internet during the pandemic. However, such claims are typically unsupported by clinical evidence, as Health Feedback’s previous reviews show.
Similarly, a video circulated on social media claiming that two botanical products could treat or mitigate COVID-19: mullein (Verbascum thapsus) leaves and marshmallow (Althaea officinalis) roots. The video recommended these herbs “if you have COVID” and added, “I drank [a tea made of those herbs] like twice a day when I had COVID and I was good in like a day”. However, there is no clinical evidence supporting such a claim.
According to the European Medicines Agency (EMA), mullein and marshmallow both have traditional medicinal uses. Mullein is traditionally used to relieve the symptoms of sore throat. It may also have expectorant, antiseptic, and anti-inflammatory properties.
Marshmallow is traditionally used to soothe the throat when irritated by dry cough. This is because it contains a substance called mucilage that, when mixed with water, produces a gel that has been shown to soothe irritated mucous membranes.
Because COVID-19 is a respiratory tract infection, it is understandable that mullein and marshmallow, among others, were considered at first as adjunct treatment for COVID-19. However, these plants’ benefits referenced in the EMA monographs are based on “plausible efficacy” and not on well-established clinical data.
Traditional use to alleviate the symptoms of sore throat isn’t enough to consider a plant as a COVID-19 treatment. In other words, without proper clinical investigation, one cannot claim that mullein and marshmallow can be used to cure or mitigate COVID-19.
Yet, a search on PubMed for scientific articles describing the therapeutic effects of mullein or marshmallow against COVID-19 returned no results. PubMed is a repository of published scientific studies hosted by the U.S. National Institutes of Health. Similarly, a search for clinical trials on ClinicalTrials.gov with available results on the use of mullein and marshmallow as COVID-19 treatment returned no results.
In conclusion, even though mullein and marshmallow are traditionally used to alleviate sore throat symptoms, there’s no scientific data available to date that support their use as a COVID-19 treatment.
- 1 – Silveira et al. (2020) COVID-19: Is There Evidence for the Use of Herbal Medicines as Adjuvant Symptomatic Therapy? Frontiers in pharmacology.