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Supplements for Seasonal Allergies: What Helps, What Doesn't, and What to Try First

For seasonal allergies (hay fever), guidelines put a steroid nose spray first (grade A), and saline rinses help (grade B). Butterbur extract is the most-studied herb (grade B), but we'd skip it: severe liver injury, including liver transplants, has occurred even with products said to be PA-free. In short trials its scores did not differ from cetirizine or fexofenadine, though an outside trial found no benefit. Probiotics and black seed help a little (grade B).

Published How we grade evidenceEditorial policy

The short version

  • Steroid nose sprays come first in allergy guidelines and beat antihistamine pills in pooled trials. Grade A (Sousa-Pinto 2026; Torres 2024).
  • Saline rinses (salt water washed through the nose) eased symptoms. Grade B (Head 2018).
  • Butterbur extract, the most-studied herb, but we'd skip it: severe liver injury has occurred even with products said to be PA-free, including 2 people who needed a liver transplant. In short trials its scores did not differ from antihistamines, but an outside team's trial found no benefit. Grade B (Schapowal 2002; Gray 2004; Anderson 2019).
  • Probiotics and black seed helped a little, with very mixed results. Grade B (Wang 2026; He 2024).
  • Spirulina helped in two small controlled trials; the one against cetirizine had no placebo group. Grade B (Cingi 2008; Nourollahian 2020).
  • Quercetin, vitamin D and stinging nettle: small, weak or mixed trials. Grade C (Lai 2025; Kawada 2025; Bakhshaee 2017).
  • Local honey did no better than corn syrup. Grade C (Rajan 2002).

What works best for seasonal allergies?

Medicines and rinses first; supplements are an add-on at most. Grade A for steroid nose sprays. The 2024 to 2025 international allergy guideline (ARIA) puts steroid sprays ahead of antihistamine sprays and pills, and suggests a spray that combines a steroid and an antihistamine over either alone (Sousa-Pinto 2026; Vieira 2026). In pooled trials of people aged 12 and older, steroid sprays eased nose and eye symptoms and improved quality of life more than antihistamine pills (Torres 2024). A US guideline strongly recommends steroid sprays when symptoms affect daily life, and less-sedating antihistamine pills for sneezing and itching (Seidman 2015).

Grade B for saline rinses. In a Cochrane review, the 6 trials (407 adults and children) that compared rinsing with no rinsing found less severe symptoms at up to 4 weeks, on low-quality evidence; no trial lasted past 3 months (Head 2018). If spring is bad every year, ask about allergy shots or tablets (immunotherapy); the US practice parameter covers both and says herbal products lack adequate studies (Dykewicz 2020). Our graded findings are on the hay fever page and hay fever protocol.

OptionWhat trials foundEvidenceGrade
Steroid nose sprayFirst in guidelines; beat antihistamine pillsGuidelines, pooled trialsA
Saline rinseMilder symptoms6 trials, low qualityB
Butterbur extract (we'd skip it: liver injury)No difference from antihistamines; outside trials mixed5 small trialsB
ProbioticsSmall gains; results vary29 trials reviewedB
Black seedMore people improved8 small trials reviewedB
Quercetin and polyphenolsFewer nose symptoms, low certainty13 trials reviewedC
SpirulinaHelped in 2 small controlled trials (one without placebo)2 trialsB
Vitamin DNo clear overall effect5 trialsC
Stinging nettleNo better than placebo in the newer trial2 trialsC
Local honeyNo better than corn syrup1 trialC

Does butterbur work for allergies?

Grade B, but we'd skip it. Severe liver injury has occurred even with products said to be PA-free, including 2 people who needed a liver transplant (see the safety section below). If you still use butterbur, do so only with your clinician and liver blood tests. Trials used tablets of a standardized extract of butterbur (Petasites hybridus), a plant in the daisy family. In 125 people with hay fever, butterbur tablets for 2 weeks gave quality-of-life and overall scores that did not differ from cetirizine; 8 of the 12 side effects on cetirizine were drowsiness or tiredness (Schapowal 2002). In 330 people, butterbur and fexofenadine each beat placebo, with no difference between them (Schapowal 2005). In 186 people, two doses both beat placebo over 2 weeks (Schapowal 2004).

Why not A: those three trials came from one research group. An outside team gave 35 people butterbur through 2 weeks of grass pollen season and saw no change in nasal airflow, symptoms or quality of life (Gray 2004); its 1-week trial in 16 people with dust mite allergy found butterbur and fexofenadine both helped (Lee 2004). A 2024 review of single-herb trials (butterbur was the most studied, with 5) found a small benefit over placebo for herbs as a group (5 trials, 249 people), at very low to low certainty (Lim 2024).

Is butterbur safe?

We'd skip it. Raw butterbur contains pyrrolizidine alkaloids (PAs), which can damage the liver and lungs and may cause cancer, and severe liver injury has occurred even with products said to be PA-free. If you still use it, do so only with your clinician and liver blood tests. NCCIH says to consider only products labeled PA-free, and reports rare liver injury even with products said to be PA-free (NCCIH). LiverTox, the US government's liver-injury database, suspects leftover alkaloids in recent cases tied to several commercial products (LiverTox).

In reports about one butterbur extract sold for migraine, 9 people had severe liver injury and 2 needed a liver transplant; 22 had also taken medicines that can harm the liver (Anderson 2019). The PubMed record's conflict-of-interest statement says the maker funded that review's lab safety studies and paid one author as an adviser. The American Academy of Neurology stopped recommending butterbur for migraine in 2015 over safety concerns (NCCIH).

Does quercetin help allergies?

Grade C. A 2025 review included 13 trials (823 people) of plant polyphenols such as quercetin and catechins. Its pooled analyses found fewer nose symptoms, at low to very low certainty, and no gain in quality of life (Lai 2025). In 66 Japanese adults with pollen allergy, 200 mg a day of an absorption-enhanced quercetin for 4 weeks improved eye itching, sneezing, runny nose and sleep scores more than placebo (Yamada 2022). A sugar-bound form eased eye symptoms, but not clearly nose symptoms, in 20 people with cedar pollen allergy (Kawai 2009). Our quercetin page describes the hay fever evidence as moderate; this guide gives C because the pooled certainty is low and the quercetin trials are small.

Do probiotics help seasonal allergies?

Grade B, for a small, inconsistent benefit. A 2026 review included 29 trials (2,078 children and adults); in its pooled analyses, probiotics improved quality-of-life and nose symptom scores, but trials and strains disagreed a lot, and the authors said high-certainty evidence for routine use is lacking (Wang 2026). Neither of the two strains tested in at least two trials, Lactobacillus paracasei Lp33 and Lactobacillus rhamnosus GG, clearly lowered nose symptoms (Farahmandi 2022).

Adult trials split. In 173 adults with self-reported seasonal allergies, a three-strain probiotic for 8 spring weeks improved allergy quality-of-life scores more than placebo (Dennis-Wall 2017). In 165 adults with grass pollen allergy, a multispecies probiotic for 8 weeks did not: 61% and 62% of the two groups improved (Cox 2023).

Does black seed oil help hay fever?

Grade B, from small, weak trials. A 2024 review included 8 trials; in its pooled analysis, more people improved on black seed (Nigella sativa) than on control (odds ratio 4.24), with brief side effects no more common; the review flags too few, low-quality trials (He 2024). Its full text shows one trial used nose drops and one a three-herb mix. In 65 adults, 250 mg of black seed oil with 2.5 mg of piperine (a black pepper compound) twice a day for 15 days lowered nose and eye symptom scores more than placebo (Majeed 2024); six authors work for the oil's seller, per the PubMed record's conflict-of-interest statement.

Does spirulina help allergies?

Grade B: two controlled trials, both positive (one double-blind placebo trial, one against cetirizine); both were small, and the cetirizine trial had no placebo group. Spirulina is a dried blue-green alga. In one double-blind trial, it eased runny nose, sneezing, blocked nose and itching more than placebo (Cingi 2008). In a 2-month single-blind trial of 53 people, not all of them adults, it beat cetirizine for runny nose, nasal blockage and lost sense of smell, with no placebo group (Nourollahian 2020). Our supplement kits page pairs spirulina with black seed in an allergy kit.

Does vitamin D help allergies?

Grade C, for no clear overall effect. Across 5 trials, the drop in symptoms against placebo was not statistically significant, and results varied hugely. Vitamin D helped only in trials where nobody was also on steroid medicines (Kawada 2025).

Does stinging nettle help allergies?

Grade C, for no clear benefit. In a 1990 trial, 69 of 98 people finished a week of freeze-dried nettle or placebo; nettle rated higher overall but only slightly higher in symptom diaries (Mittman 1990). In a 2017 trial of 74 people, a 150 mg root extract for a month did no better than placebo, and only 40 finished (Bakhshaee 2017). Our stinging nettle page shows "Improves" from the 1990 trial alone.

What about perilla, tinospora and astragalus?

  • Perilla: in 29 people with mild hay fever, 21 days of a rosmarinic acid-rich extract gave more responders for itchy nose and eyes than placebo. Grade C (Takano 2004).
  • Tinospora (guduchi): in 75 people, 8 weeks of an extract relieved nose symptoms far more often than placebo. Grade C (Badar 2005).
  • Astragalus: in 48 adults, a herb-and-mineral product containing it improved only runny nose among the main measures. Grade C (Matkovic 2010).

What we'd skip

  • Local honey. In 36 people, a tablespoon a day of local raw honey or store honey did no better than flavored corn syrup (Rajan 2002). A trial in 40 people on an antihistamine reported benefit from a much larger amount, 1 g of honey for every kilogram of body weight daily (Asha'ari 2013).
  • Vitamin C pills. Adding 2,000 mg a day to 8 weeks of exercise showed no benefit the 27-person trial could detect (Tongtako 2018); upper limit for adults: 2,000 mg of vitamin C a day, because more can cause diarrhea and stomach upset (NIH ODS). A 2025 review found oral vitamin C does not appear to change hay fever risk (Trincianti 2025).
  • Fish oil. In 22 people already on a steroid spray and allergy shots, 2 months of high-dose EPA and DHA made no difference to symptoms (Armenta-Morales 2025).
  • Bromelain. We found no trial in adults with hay fever; the one study we found was in children with acute sinusitis (Braun 2005).
  • Butterbur, including products labeled PA-free: severe liver injury, though rare, has been reported with products said to be PA-free (NCCIH), including 9 severe cases and 2 liver transplants with one extract sold for migraine (Anderson 2019). Raw butterbur and homemade butterbur tea contain liver-damaging alkaloids. If you still use it, do so only with your clinician and liver blood tests.

Safety and interactions

  • Butterbur: belching, diarrhea, drowsiness, rash and upset stomach; allergic reactions in people allergic to ragweed, chrysanthemums, marigolds or daisies (NCCIH). Talk with your provider first if you take any medicine.
  • Quercetin: in 12 healthy volunteers, 500 mg twice a day (the amount our protocol lists) for 10 days raised blood levels of the painkiller diclofenac (Bedada 2018). Ask your pharmacist if you take prescription medicines.
  • Black seed: in a trial of 94 people with type 2 diabetes on medicines, 2 g a day of black seed capsules lowered HbA1c (a 3-month blood sugar measure) by 1.52%, so watch for low blood sugar (Bamosa 2010). A possible bleed was reported in a man on two antiplatelet drugs (case report) (Arab 2026).
  • Spirulina: LiverTox calls liver injury from it very rare, if it happens at all (LiverTox). In a test of 17 brands of blue-green algae supplements in Italy, spirulina-only products were free of liver toxins (microcystins), but products made from another alga were contaminated (Vichi 2012).
  • Probiotics: harm is more likely with severe illness or a weakened immune system, and some products hold microbes not on the label (NCCIH). On antibiotics? Read can I take probiotics with antibiotics? and ask your prescriber or pharmacist.
  • Antihistamines: some cause sleepiness, so don't drive or use machines after taking one (MedlinePlus).
  • Stacks: check your stack against the upper limits.

When to see a doctor

  • Call 911 if your throat swells, your voice turns very hoarse or whispery, or you struggle to breathe after exposure to something you are allergic to. That can be anaphylaxis (MedlinePlus).
  • Book a visit if symptoms are severe, a treatment that worked stops working, or nothing helps (MedlinePlus). A US guideline asks clinicians to offer allergy testing when treatment fails, and to check for asthma and sinus disease (Seidman 2015). Wheezing needs an asthma check; facial pain may point to sinusitis.
  • On butterbur: stop it and get medical care for yellowing skin or eyes, or dark urine; our liver guide lists the warning signs.
  • Don't stop a prescribed medicine on your own; ask the prescriber or pharmacist. If you are pregnant, breastfeeding or under 18, ask a clinician (your doctor or midwife) first.

FAQ

What is the best natural remedy for seasonal allergies? Saline rinses, a non-drug option, eased symptoms in a Cochrane review of small trials (grade B). Among herbs, butterbur extract has the most trials (grade B), but we'd skip it because of severe liver injury reports, even with products said to be PA-free.

Does butterbur work as well as an antihistamine? In three short trials, butterbur scores did not differ from cetirizine or fexofenadine. That does not settle it: two of the three came from one research group, and another team's placebo-controlled trial found no benefit. We'd skip it anyway because of liver injury reports.

Is butterbur safe? We'd skip it. Raw butterbur contains pyrrolizidine alkaloids that can damage the liver, and severe liver injury, though rare, has occurred even with products said to be PA-free, including 9 severe cases and 2 liver transplants with one extract sold for migraine. If you still use it, do so only with your clinician and liver blood tests.

Does quercetin help allergies? Possibly a little (grade C). In 66 adults with pollen allergy, 200 mg a day for 4 weeks improved several symptoms, but pooled trials of quercetin-type compounds are low to very low in certainty.

Does local honey help allergies? Not in the only placebo-controlled trial of local honey: a tablespoon a day did no better than corn syrup in 36 people (grade C).

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