Burdock root: two small trials and two poisonings

Burdock is sold as a root, a tea and a capsule, and the research has tested the capsule and the tea. The best of it is a randomised placebo-controlled trial in sixty women with polycystic ovary syndrome, half of whom took 460 mg of root powder a day for twelve weeks. Every marker of oxidative stress and inflammation the researchers measured moved in the better direction, nobody dropped out, and nobody reported a side effect. Thirty women over twelve weeks is too small a group and too short a time to turn up a rare harm, so that last sentence says less than it sounds like. A second trial gave 36 people with knee osteoarthritis three cups of root tea a day for six weeks alongside their painkillers, and interleukin-6, hs-CRP and malondialdehyde all fell. Both trials measured blood, and neither result we hold reports pain, symptoms or how anyone felt. Everything else about burdock is laboratory work on two plant compounds, arctigenin and arctiin. The whole extract showed no toxicity in that work, while arctigenin on its own was toxic at a high enough dose. We have no USDA composition entry for burdock, so this page has no nutrition table.

How much is actually in it

• The compounds burdock is bought for are spread through the whole plant, and the root holds the most of them. — published chemical analyses of burdock root, seed and leaf Evidence E source
  Tannins, polyphenols such as caffeic and chlorogenic acid, the dietary fibre inulin, the lignans arctigenin and arctiin, sterols, essential oils, vitamins, minerals and amino acids are listed across the plant, with the root richest in them

What cooking and storage change

• Factory-packaged burdock tea can carry more of an atropine-like alkaloid than tea prepared the traditional way. — one 26-year-old woman who came to an emergency department after drinking an infusion of Arctium lappa (n = 1 case) Evidence E source
  Visual impairment, urinary retention, dry mouth and abnormal behaviour consistent with anticholinergic toxicity; mass spectrometry found elevated amounts of an atropine-like alkaloid in the commercially packaged tea, which the authors attribute to industrial cultivation and processing

What it does to your health

• Three cups of burdock root tea a day for six weeks lowered inflammatory markers in people with knee osteoarthritis who were already taking painkillers. — 36 patients, 10 men and 26 women, aged 50 to 70 with knee osteoarthritis at a rehabilitation department in Tabriz, Iran (n = 36) Evidence B source
  Serum IL-6 fell (P=0.002), hs-CRP fell (P=0.003) and malondialdehyde fell (P<0.001), while total antioxidant capacity rose (P<0.001) and superoxide dismutase activity rose (P=0.009); GPX rose without reaching significance

Safety, limits and interactions

• One reported case of serious liver injury followed an over-the-counter herbal tea whose first listed ingredient was burdock root. — one 36-year-old woman (n = 1) Evidence D source
  Clinically significant acute liver injury attributed to a herbal tea containing burdock root, stinging nettle leaf, cleavers herb, dandelion root, lemon peel and lemon myrtle leaf; the authors record it as the first reported hepatotoxic effect from any of these ingredients
• Thirty women took a measured 460 mg of burdock root powder daily for twelve weeks and none of them reported a side effect, which is too few people over too short a time to find a rare harm. — women aged 18 to 45 with polycystic ovary syndrome, half on burdock root powder and half on starch placebo (n = 60) Evidence B source
  All 60 participants completed 12 weeks without dropping out and no side effects were reported over the trial

What people believe that the data does not support

• In the one review of clinical trials where burdock appears, what was tested was a multi-ingredient burdock complex, and it was not effective as a single agent against stomach bacteria, only alongside standard drug therapy. — 24 clinical studies, 15 of vegetable extracts and 9 of micronutrients (n = 24 studies) Evidence C source
  Broccoli sprouts, curcumin, burdock complex, Nigella sativa, vitamin C and vitamin E were not effective as single agents against H. pylori, and their effect appeared only alongside conventional drug therapy; GutGard was significantly effective alone against placebo

Who this works differently for

• In women with polycystic ovary syndrome, 460 mg of burdock root powder a day for twelve weeks moved every measured marker of oxidative stress and inflammation in the better direction. — women aged 18 to 45 with polycystic ovary syndrome diagnosed by Rotterdam criteria, not intending to become pregnant (n = 60, no dropouts) Evidence B source
  Versus placebo the burdock group rose in SOD, CAT, GPx, TAC, TAG, TT, GSH/GSSG and GSH and fell in TOS, OSI, MDA, MDA/TAC, BAR, ALBI, CAR, GSSG, CRP and both left and right ovarian volume, all p<0.05; ANCOVA adjusted for baseline confirmed these and added a fall in the TyG index

What is still unknown

• Everything interesting about burdock rests on two lignans studied in laboratories, and one of them is toxic at a high enough dose. — published literature on Arctii Fructus, the fruit of the burdock plant Evidence D source
  More than 200 compounds identified, chiefly lignans, phenolic acids, fatty acids, terpenoids and volatile oils; the lignans arctigenin and arctiin carry the anti-cancer, antiviral and anti-inflammatory activity described; the extract showed no toxicity while arctigenin was toxic at a certain dose

The bottom line

If you drink burdock tea because you like the taste, that is a fine place to leave it. Two things are worth knowing before you take it as a remedy. A 36-year-old woman developed clinically significant acute liver injury after an over-the-counter herbal tea whose listed ingredients began with burdock root, and the authors record it as the first such case for any ingredient in that blend. A 26-year-old woman reached an emergency department with visual impairment, urinary retention, dry mouth and abnormal behaviour after an infusion of burdock. Mass spectrometry found raised amounts of an atropine-like alkaloid in the commercially packaged tea, which the authors attribute to industrial growing and processing rather than to the plant. Two case reports cannot tell you how often this happens. They can tell you that a packaged herbal tea is not automatically the mild option. One popular use has been tested. Against the stomach bacterium Helicobacter pylori, what the one review of clinical trials covers is a multi-ingredient burdock complex rather than the root, and it was not effective as a single agent, showing an effect only alongside standard drug therapy. The trial that produced the best number here enrolled only women who were not intending to become pregnant, so it says nothing about pregnancy. And the trial dose was a measured 460 mg of powder, while a mug of tea is not measured at all.

Sources

1. brd-dr-08 · narrative review
   These components are abundantly present throughout the entire plant, although the roots exhibit a higher concentration of these bioactive constituents
   Natural Products and Bioprospecting, 2024 · checked 2026-09-22
2. brd-dr-07 · narrative review reporting a case with chemical analysis
   The production of A. lappa L. tea in the industrial setting involves various cultivation and processing techniques that lead to higher levels of alkaloids compared to traditional or homemade preparations.
   Natural Products and Bioprospecting, 2024 · checked 2026-09-22
3. brd-dr-06 · randomized controlled trial
   The results showed that burdock root tea significantly decreased the levels of serum IL-6 (P = 0.002), hs-CRP (P = 0.003) and malondialdehyde (P < 0.001), while the levels of serum TAC (P < 0.001) and activities of SOD (P = 0.009) were significantly increased.
   Int J Rheum Dis, 2016 · checked 2026-09-22
4. brd-dr-02 · case report
   This is the first case reported of a hepatotoxic effect from any of these compounds or ingredients in the detox tea: burdock root, stinging nettle leaf, cleavers herb, dandelion root, lemon peel, and lemon myrtle leaf (Backhousia citriodora).
   Case Rep Gastroenterol, 2022 · checked 2026-09-22
5. brd-dr-05 · randomized double-blind placebo-controlled trial
   All 60 participants completed the study without any dropouts, and importantly, no side effects were reported throughout the trial
   JBRA Assisted Reproduction, 2026 · checked 2026-09-22
6. brd-dr-03 · review of clinical trials
   Vegetable extracts (Broccoli sprouts, curcumin, Burdock complex, and Nigella sativa) and micronutrients (vitamin C and E) were not found to be as effective as single agents in H. pylori eradication, rather their efficacy synergized with conventional pharmacological therapies.
   Molecules, 2021 · checked 2026-09-22
7. brd-dr-04 · randomized double-blind placebo-controlled trial
   Statistical analysis using independent t-test at the end of the trial revealed that the AL group showed significant increases in the following outcomes compared to the placebo group: SOD, CAT, GPx, TAC, TAG, TT, GSH/GSSG, and GSH (all p<0.05).
   JBRA Assisted Reproduction, 2026 · checked 2026-09-22
8. brd-dr-01 · systematic review of preclinical and ethnopharmacological literature
   Although Arctii Fructus extract had no toxicity, arctigenin was toxic at a certain dose.
   J Ethnopharmacol, 2023 · checked 2026-09-22