Echinacea and Colds: What the Cochrane Review Found
Come winter, echinacea is one of the first herbs people reach for. It’s been sold for colds for more than a century. But the research has been something of a roller-coaster, with headlines swinging from “it works” to “it doesn’t”. This guide explains what the biggest reviews found and why the answer is less tidy than you might hope.
What is echinacea?
Echinacea is a group of daisy-family plants native to North America, often called purple coneflowers. Three species are mostly used: Echinacea purpurea, E. angustifolia and E. pallida. Different products use different species and different parts of the plant: the root, the flowers and leaves, or the whole plant.
Indigenous peoples of the Great Plains used echinacea for many purposes. It became popular in American herbal medicine in the late 1800s and later in Europe, especially Germany.
What’s in it?
Echinacea contains a mix of compounds, including alkamides (which cause the tingly feeling on the tongue), caffeic acid derivatives such as cichoric acid, and polysaccharides. Their levels vary a lot between species, plant parts, growing conditions and processing. That variation turns out to be important when we look at the research.
The 2007 meta-analysis: an optimistic result
In 2007, a meta-analysis in The Lancet Infectious Diseases pooled 14 studies (Shah et al., 2007). It reported that echinacea was linked with lower odds of catching a cold and a shorter cold, by about a day and a half on average.
The paper made headlines. But other researchers raised concerns, including how different the pooled studies were, the products used and the risk of bias in some trials. That set the scene for a more cautious review.
The 2014 Cochrane review: a more careful answer
The Cochrane Collaboration’s review is generally seen as the most rigorous look at the question (Karsch-Völk et al., 2014). It included 24 randomised controlled trials with more than 4,600 participants. Its main findings were:
- For treating colds, echinacea products overall did not show a clear benefit over placebo. A weak effect for some E. purpurea preparations couldn’t be ruled out.
- For preventing colds, results suggested a possible small effect. When the prevention trials were pooled, there was a small reduction in risk, but individual trials mostly didn’t show a significant difference.
- Products varied enormously. Because the trials tested such different preparations, the reviewers said it’s hard to generalise about “echinacea” as a whole.
The authors concluded that echinacea products have not been shown to provide benefits for treating colds, although some preparations may have a weak effect.
Why do the reviews disagree?
The two reviews don’t really contradict each other as much as it first seems. They included different studies, used different methods, and were working with a mix of products that weren’t directly comparable. When the evidence is a patchwork like this, results often shift depending on which pieces are put together. The honest answer is that echinacea’s effect on colds, if any, appears to be small and uncertain.
What this means for you
For most healthy adults, colds get better on their own within a week or so. Rest, fluids and time are the mainstays. Echinacea isn’t a proven way to prevent or treat a cold, and it isn’t a substitute for seeing a doctor if you have a high fever, trouble breathing or symptoms that won’t go away.
Enjoying echinacea as a tea
Many people simply enjoy echinacea as part of a winter tea routine:
- Use about 1–2 teaspoons of dried herb per cup.
- Pour over just-boiled water, cover and steep for 10–15 minutes. Roots may need longer, or a gentle simmer.
- The taste is earthy and floral, with a slight tongue tingle. It blends well with lemon, ginger or honey.
Who should take care?
Echinacea belongs to the daisy family (Asteraceae). People allergic to plants such as ragweed, chrysanthemums, marigolds or daisies may react to it, and rare serious allergic reactions have been reported. People with asthma or atopic conditions should be cautious. Because it’s thought to act on the immune system, people with autoimmune conditions, or who take immune-suppressing medicines, should check with their doctor. Talk to your pharmacist if you take regular medication, or if you’re pregnant or breastfeeding.
The bottom line
Echinacea has a long history and plenty of research. But the best review to date found no clear benefit for treating colds and, at most, a small possible effect for prevention. The products tested vary so much that it’s hard to say anything definite about echinacea as a whole. Enjoy it as a warming tea if you like it, and look after the basics when a cold strikes.
This article is general information only and is not medical advice. It is not about any specific product. Talk to your GP or pharmacist about your own health.
References
- Karsch-Völk M, et al. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev. 2014. https://pubmed.ncbi.nlm.nih.gov/24554461/
- Shah SA, et al. Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis. Lancet Infect Dis. 2007. https://pubmed.ncbi.nlm.nih.gov/17597571/
