Nettle Tea for Hay Fever: Two Trials, Neither of Them Tea

Two randomised controlled trials have tested stinging nettle for hay fever in the thirty six years since the first one was published. There is a problem with both of them, and it is not the sample size. This page sets out what each trial actually gave people, what it measured, who ran it, and why the gap between those trials and the mug in your hand is wider than any review of nettle will tell you.

The Evidence at a Glance

The Short Answer

Nobody has tested nettle tea for hay fever. The 1990 trial used freeze-dried leaf in capsules and ran for one week. The 2017 trial used a 150 mg root extract tablet, and in that trial the placebo group improved just as much. Nettle tea is an infusion of the leaf, which means the older trial is the only one that tested anything like the right part of the plant, in a form nothing like a cup of tea, on 69 people who finished, over seven days. That is the whole human evidence base. It is not enough to call nettle tea an antihistamine, and it is also not enough to call it useless, because the question has not been asked properly. For where it sits against everything else, see our ranked guide to natural remedies for hay fever, where saline rinsing, not a herb, is the best evidenced measure on the list.

Leaf, Root, and Why the Difference Decides Everything

Stinging nettle, Urtica dioica, is sold as two quite different medicines, and herbal pharmacy has treated them as separate for decades.

• The leaf, sometimes sold as nettle herb. This is what a nettle teabag contains, and what you would pick and dry yourself. Traditionally a spring tonic and a diuretic.
• The root. A different plant part with a different chemistry, sold as a standardised extract in tablets. Its recognised use is nothing to do with allergy.

How separate they are is easiest to see in the research. The standard pharmacological review of nettle root, Chrubasik and colleagues in Phytomedicine in 2007, opens by stating what the root is for: complaints associated with benign prostatic hyperplasia, an enlarged prostate. Search the trial literature for nettle root and that is almost all you find, trial after trial in men with urinary symptoms.

So when the 2017 hay fever trial reached for a nettle root extract, it reached for the plant part whose entire research tradition is the prostate. That is not a reason to dismiss the trial, but it is a reason not to carry its result across to a teabag. Nobody would take a finding about a pomegranate seed extract and apply it to pomegranate juice without checking, and the leaf and root of a nettle are further apart than that.

1990: the Trial Everyone Cites, Read Properly

Almost every page that recommends nettle for hay fever is resting, at one or two removes, on a single study: Mittman, Planta Medica, February 1990. It is a genuine randomised, double-blind, placebo-controlled trial, which in 1990 in this field was not common, and it deserves to be read rather than summarised.

• 98 people were randomised and 69 completed. Twenty-nine did not finish, which is thirty per cent of everyone who started.
• It ran for one week. Hay fever seasons run for months.
• It used a freeze-dried preparation of nettle, in capsule form, not an infusion.
• There were two outcomes, and they did not agree.

That last point is the one that never survives into the summaries. People kept daily symptom diaries, and they also gave a single global verdict at a follow-up visit at the end of the week. On the global verdict, nettle came out ahead of placebo. On the diaries, in the paper’s own words, nettle was “rated only slightly higher”.

Those two measures are asking different questions. The diary asks how you feel today. The global rating asks what you think of the week you have just had, after the fact, while holding a bottle of something you hope has worked. When the recalled impression beats placebo and the day-by-day record barely moves, the gap between them is the interesting result, and it points toward expectation doing some of the work. The abstract reports no effect size, no confidence interval and no p value for either outcome, so there is no number here to quote at all. The trial was run at a naturopathic college in Portland, Oregon.

None of that makes it a bad study for 1990. It makes it a small, short, single-centre trial with high dropout and a split result, which is a thin foundation for thirty six years of recommendations.

2017: the Newer Trial, Where Placebo Kept Pace

A second randomised trial does exist, and it is better measured than the first: Bakhshaee and colleagues, Iranian Journal of Pharmaceutical Research, 2017, run across ear, nose and throat and allergy centres at Mashhad University of Medical Sciences. Seventy-four people with allergic rhinitis symptoms and a positive skin prick test were randomised to a 150 mg nettle root extract tablet or placebo for one month. Forty completed, so the dropout was higher again, at forty-six per cent.

It measured symptoms on the SNOT-22 questionnaire and then went looking for the mechanism in blood and nasal samples. The results, taken one at a time:

• Symptoms improved significantly, p less than 0.001, in both groups. The nettle arm got better. So did the placebo arm, by a similar amount.
• Eosinophils on a nasal smear, the allergy cell you would expect to fall, did fall after nettle, p less than 0.01, measured within the group before and after.
• IgE, interleukin-4 and interleukin-5, the three markers most central to an allergic response, showed no significant change at all, p greater than 0.1.
• Interferon gamma did differ between the groups after treatment, p equals 0.017.

The authors’ own conclusion is unusually candid and worth quoting rather than paraphrasing: although the trial showed “certain positive effects of Nettle in the management of allergic rhinitis on controlling the symptoms based on the SNOT-22”, they write, “similar effects were demonstrated by placebo as well”. They end by calling for larger and longer studies.

So the two trials in this literature point in opposite directions in a particular way. The older, shorter one found a benefit on the measure most open to expectation. The newer, longer one watched placebo match the herb, and found the allergy markers you would need to move largely unmoved. And it was testing the root.

“Nettle Blocks Histamine”: Where That Comes From

The mechanism is the part of the nettle story that sounds most like science, and it rests on two papers. Neither one involved a person, and neither one used tea.

The first is Roschek and colleagues, Phytotherapy Research, 2009. A nettle extract was put in contact with isolated receptors and enzymes and it did block them: it antagonised the histamine-1 receptor, inhibited mast cell tryptase, and inhibited COX-1, COX-2 and prostaglandin D2 synthase. That is a real finding, and it explains why the claim exists.

The part nobody quotes is the concentrations required, which the paper reports plainly:

Those are concentrations in a dish, bathing a target directly. The paper makes no claim about what any of this does inside a body, offers no measurement of how much nettle extract reaches the blood, and describes its own achievement as a mechanistic understanding “in vitro”. We are not going to convert these figures into cups of tea, because the paper supplies nothing to convert with, and anyone who does that conversion for you has invented the missing step. One more thing belongs on the record, because the paper discloses it: the authors were working at HerbalScience Group LLC, a supplement company in Naples, Florida.

The second paper is newer and, in a way, stranger. Culhuac and Bello, Molecules, April 2024 is the most recent study published on nettle and allergic rhinitis, and it is a computer simulation. Nettle compounds were docked against five allergy targets in software, and four of them, including amentoflavone and alpha-tocotrienol, bound well in the model. The paper’s own next step is to call for laboratory and animal work. It is a reasonable piece of research and it is upstream even of the dish. The newest thing anyone has published about nettle for hay fever involves no nettle.

How That Compares With Herbal Hay Fever Research in General

It would be unfair to hold nettle to a standard nothing in this field meets, so here is the field. In 2024 a team at the Herbal Medicine Research Centre of Malaysia’s Institute for Medical Research published a systematic review and meta-analysis of single medicinal plants for allergic rhinitis: Lim and colleagues in PLoS One. They found 29 randomised trials covering 1,879 people in total.

• Against placebo, single plants may improve total nasal symptoms, a standardised mean difference of 0.31 in favour of the herbs, on 249 participants across five studies, rated very low to low certainty.
• Against an antihistamine, there was no clear difference in overall symptoms, on moderate certainty evidence.
• The most studied single plant was butterbur, Petasites hybridus, with five trials. Not nettle.
• The reviewers’ summary: “Clear beneficial evidence of medicinal plants for allergic rhinitis is still lacking.”

Two points follow. The first is that nettle is not the weak link in a strong field, it is a thin strand in a thin field. The second is the comparison with butterbur, which has five trials to nettle’s two and is the one herb on our main hay fever page with meaningful evidence behind it. If you are choosing a herb because of the research, the research does not point at nettle.

So What Is a Cup of Nettle Tea Actually Good For?

A warm drink, and a pleasant one. That sounds like a let-down and it is not meant to be, because during a bad spell of hay fever the warm drink is doing something real: it is fluid, it is comforting, and it gives you a reason to sit still for ten minutes. Nobody has measured nettle tea against allergic rhinitis, so “untested” is the honest word, not “useless”. Those are different findings and this page is not going to slide from one to the other.

What has been measured, repeatedly and with good trials behind it, is rinsing pollen out of your nose with salt water. If you want a ten minute ritual that affects your symptoms, that is the one with the evidence, and we have a guide to using a neti pot safely. Have the tea as well.

Who Should Leave Nettle Alone

Nettle leaf as a drink has a long food history and the 2024 review found medicinal plants generally well tolerated for up to eight weeks of use. That is reassurance about the category, not a safety clearance for you, and there are people who should ask first rather than experiment.

• If you take any prescribed medicine, and particularly a blood thinner, a diuretic, a blood pressure medicine or a diabetes medicine, ask a pharmacist before adding nettle in any form. Nettle leaf has a traditional diuretic use, which is exactly the kind of effect that stacks with a prescription.
• If you are pregnant or breastfeeding, leave it. There is no trial evidence to go on and traditional use in pregnancy is contested.
• If your hay fever is severe, or it is reaching your chest, or an antihistamine is not holding it, that is a conversation with a pharmacist or a GP about stepping treatment up, not a reason to try a herb.
• Nettle pollen is itself an allergen. A 2016 paper in Annals of Allergy, Asthma and Immunology characterised genuine allergy to Urtica dioica pollen. It is uncommon, and a dried leaf infusion is not a pollen exposure, but if nettles have ever made you react other than by stinging your skin, take that seriously.

Nothing on this page is a dose. Two trials exist, one used an unstated amount of a freeze-dried leaf preparation and the other used 150 mg of a root extract, and there is no established tea dose for hay fever anywhere in this literature. Anyone quoting you one has made it up.

When to See a Doctor

See a pharmacist or GP if your symptoms are not controlled by an over the counter antihistamine, if you are wheezing, short of breath or your chest feels tight, if symptoms last beyond the pollen season or appear all year round, or if you are considering stopping a prescribed treatment in favour of something herbal. Hay fever that reaches the lungs is treated differently from hay fever that stops at the nose, and that distinction is a clinical one.

Frequently Asked Questions

Does nettle tea actually work for hay fever?

Nobody has tested it. The two randomised trials of nettle for hay fever used freeze-dried leaf capsules in 1990 and a root extract tablet in 2017, not an infusion. In the 2017 trial the placebo group improved as much as the nettle group. That leaves nettle tea untested rather than disproved.

Is nettle a natural antihistamine?

A nettle extract blocked histamine-1 receptors in a 2009 laboratory study, at concentrations between 193 and 251 micrograms per millilitre in a dish. That is a test tube result, the paper offers no measurement of what reaches the bloodstream, and no trial has shown a cup of nettle tea doing anything comparable in a person.

How much nettle tea should I drink for hay fever?

There is no established amount, because there is no trial of nettle tea for hay fever to take one from. The two trials used capsules and tablets, and one of them did not state its quantity. Treat any specific figure you are given elsewhere as invented.

Should I use nettle leaf or nettle root?

They are different medicines. Nettle root’s recognised use is for the urinary symptoms of an enlarged prostate, and almost all of its trials are in that area. Nettle leaf is what a teabag contains and what the 1990 hay fever trial used, in a freeze-dried form. Evidence about one does not transfer to the other.

Is nettle better than butterbur for hay fever?

On the amount of evidence, no. The 2024 meta-analysis of 29 herbal trials found butterbur the most studied single plant with five trials, against nettle’s two. Butterbur also carries a real safety condition, in that only certified PA-free extracts are safe because the raw plant is toxic to the liver.

Can I drink nettle tea with my antihistamine?

There is no trial evidence on that combination either way. Nettle leaf has a traditional diuretic action and may interact with blood thinners, blood pressure medicines and diabetes medicines, so the combination to check is with your prescriptions rather than with the antihistamine, and a pharmacist is the person to ask.

Related Guides

• Natural remedies for hay fever, ranked by evidence
• Quercetin for hay fever: what the trials actually measured
• How to use a neti pot safely