Hydrangea is a popular decorative plant because of its blue and lavender-colored flowers. It belongs to the Hydrangeaceae family.

Its root and rhizome — or underground stem — have been used traditionally as herbal medicine to treat urinary conditions.

However, you may wonder what science has to say about its acclaimed benefits and safety.

This article explores hydrangea root’s benefits, uses, supplements, side effects, and dosage.

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The genus Hydrangea is made up of over 70 plant species that belong to the Hydrangeaceae family (1).

Out of these, Hydrangea paniculata, Hydrangea macrophylla, and Hydrangea arborescens are the most popular when it comes to medicinal properties.

H. paniculata and H. macrophylla are native to Asia, while H. arborescens is native to the eastern United States.

Other common names for these species include hortensia, seven bark, wild hydrangea, smooth hydrangea, bigleaf hydrangea, and mophead hydrangea.

Hydrangea root is a supplement made from these plant’s roots and underground stems, also known as the rhizomes.

The supplement has been used in folk medicine for hundreds of years to treat prostate and bladder infections due to its purported diuretic effects — meaning its ability to increase urine output. However, no available scientific evidence backs up this claim.

It’s also speculated that it might help treat kidney and bladder stones and enlarged prostate.


Hydrangea root is a supplement made from various hydrangea plants. It’s traditionally used to treat urinary tract infections and stones.

Test-tube and animal studies suggest that some hydrangea root compounds may provide medicinal benefits.

May protect your kidneys

Elevated levels of certain blood markers are associated with kidney injury. Studies in mice indicate that hydrangea extract may lower some of these markers (2, 3).

For example, high levels of blood urea nitrogen (BUN) indicate kidney damage. Studies in animals with medically induced kidney injury found that hydrangea extract significantly reduced BUN levels (3, 4).

One of these studies also observed less kidney damage in mice treated with the extract, compared with a control group (3).

Another study similarly found that skimmin, an active molecule found in hydrangea extract, reduced BUN, blood creatinine, and urinary albumin excretion (UAE) in mice with kidney inflammation. High creatinine and UAE levels also indicate kidney dysfunction (5).

What’s more, research in mice determined that the extract improved medicinally induced kidney injury by downregulating kidney inflammation and cell death, although the effect was only observed in cases of previously damaged kidneys (2).

Still, despite these promising results, human studies are needed.

May have anti-inflammatory properties

Hydrangea root is rich in a compound called coumarin. Both coumarin and its derivative skimmin may offer anti-inflammatory properties.

Inflammation can lead to increased levels of tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), nitric oxide (NO), and interleukin 6 (IL-6) — all of which are known as pro-inflammatory markers (6).

Animal research suggests that both coumarin and skimmin may inhibit NO production and IL-6 activation and suppress the upregulation of TNF-α and IL-1β (2, 3, 5).

Additionally, in one study in mice hydrangea root extract inhibited the infiltration of inflammatory cells like macrophages and neutrophils into kidney tissue, which suggests another potential anti-inflammatory mechanism (2).

Lastly, in addition to coumarin and skimmin, the extract contains loganin and sweroside, two compounds known for their anti-inflammatory activities (2).

All this being said, keep in mind that research in humans is lacking.

May have antioxidant effects

If there are too many reactive oxygen species (ROS) in your body, a phenomenon called oxidative stress can occur, which can lead to tissue damage and other detrimental health effects (7).

Thankfully, molecules known as antioxidants protect against oxidative stress and said damage (8).

Coumarins in hydrangea root have antioxidant properties. For example, a mouse study found that hydrangea extract significantly reduced oxidative stress, suggesting potent antioxidant effects (2).

Similarly, another study determined that the extract significantly lowered oxidative stress markers such as NO and malondialdehyde (MDA) in mice (3).

It’s important to note that these benefits have not been confirmed in research in humans.

Other potential benefits

While research in humans is lacking, it’s speculated that hydrangea root may also:

  • Lower blood sugar levels. Test-tube studies and animal research indicate that the compound skimmin in hydrangea root may relieve insulin resistance and enhance blood sugar uptake (9).
  • Protect your liver. Test-tube research has found multiple compounds in hydrangea stems that may protect from liver toxicity (10, 11).
  • Provide cancer-fighting properties. One test-tube study determined that hydrangenol, another compound present in hydrangeas, may inhibit bladder cancer cell reproduction and spread (12).

Hydrangea root may protect from kidney damage and provide antioxidant and anti-inflammatory effects, among other benefits. However, keep in mind that research in humans is needed.

There’s little research on hydrangea root side effects and toxicity.

Anecdotally, user reports have described potential side effects like chest tightness, upset stomach, nausea, vomiting, and dizziness.

Also, according to an older study from 2000, the compound hydrangenol — an allergen in hydrangeas — may cause allergic reactions when hydrangea root comes in direct contact with the skin (13).

Lastly, due to the lack of information regarding the toxicity of the root, people who are pregnant or breastfeeding should avoid its use.

Make sure to consult your healthcare provider before consuming hydrangea root supplements.


There’s little research regarding hydrangea root toxicity. However, anecdotally reported side effects include nausea, upset stomach, dizziness, chest tightness, and vomiting.

You may find hydrangea root supplements online in capsule, tincture, powder, syrup, and liquid extract forms.

Dried or powdered hydrangea root is often made into tea, prepared by simmering 1 tablespoon (15 grams) of the supplement in an 8-ounce (250-mL) cup of water (14).

Due to the lack of research in humans, there’s currently no dosage recommendation for hydrangea root supplements.

However, doses higher than 2 grams have been linked to the previously mentioned side effects.


You may find hydrangea root in powder, tincture, syrup, and capsule form. There’s currently no established dosage for the supplement, though it’s speculated that taking over 2 grams could cause unwanted side effects.

Hydrangea root has been used for hundreds of years to treat urinary conditions like prostate and bladder infections, enlarged prostate, and kidney and bladder stones.

However, test-tube and animal research only back up its use as a possible way to protect your kidneys from injury. Additionally, it’s speculated that some of its plant compounds may provide anti-inflammatory and antioxidant activities.

It’s important to note that human research on all of its purported benefits is lacking. This also means that there’s no established dosage for the supplement, and its use may cause side effects such as nausea, vomiting, upset stomach, and dizziness.

You may find hydrangea root supplements in various forms, including capsules, tinctures, powder, syrup, and liquid extracts.