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Botanical illustration of Cat's Claw
MedicinalSourced entry

Cat's Claw

Uncaria tomentosa

A woody vine from the Amazon rainforest, named for its hooked thorns, used by Indigenous Amazonian peoples for centuries and now promoted for arthritis. There's no conclusive evidence it helps any health condition.

Safety at a glance

Tap a box to read the safety notes below. “Nothing recorded” means our sources don't cover it, not that it's safe.

Cat's Claw may interact with some medicines. If you take any medicine, read Interactions with medicines below and talk to your doctor or pharmacist before using it.

What is Cat's Claw?

Plant family
Rubiaceae, the coffee family
Parts used
The bark and root of the woody vine
Where it grows
The Amazon rainforest and other tropical areas of Central and South America
Genus
Uncaria
Species
tomentosa

Also called

Cats Claw

Regional names

Uña de Gato

Older scientific names

Uncaria guianensis

Traditionally used for

  • Arthritis (promoted)
  • Immune support (promoted)
  • Traditional Amazonian remedy

Traditionally described as

  • May stimulate the immune system

Health topics

Where Cat's Claw appears in symptom search, and why. Being listed doesn't mean it's a proven treatment.

  • Joint Discomfort

    Promoted for osteoarthritis and rheumatoid arthritis, but there's no conclusive evidence from studies in people.

How it's prepared

Common ways Cat's Claw is prepared or sold. This isn't advice on how to take it; see Safety below.

Safety

Interactions with medicines

  • Cat's claw may slow blood clotting and increase bleeding during surgery. It may interact with blood thinners, anti-platelet medicines and blood pressure medicines.[2]Health agency

Who should avoid it

  • Cat's claw may stimulate the immune system, which could make autoimmune diseases worse. It's considered safe to take by mouth for up to 6 months.[2]Health agency

Pregnancy

  • Some studies suggest cat's claw is unsafe during pregnancy. Its safety while breastfeeding is unknown.[2]Health agency

What does the research say?

Traditional use

These are traditional uses, not proven treatments.

  • Indigenous peoples of the Amazon have used cat's claw for centuries to prevent illness. Today it's promoted for osteoarthritis, rheumatoid arthritis, cancer, viral infections and COVID-19. Most products sold in the US contain Uncaria tomentosa.[2]Health agency

Research in people

  • There's no conclusive evidence from studies in people that cat's claw helps any health condition. Many of the existing studies were poorly designed or too small.[2]Health agency

  • In a small 2001 study, 12 healthy adults were split into 3 groups: 250 mg or 350 mg a day of a water extract of cat's claw (Uncaria tomentosa) for 8 weeks, or nothing. When their blood cells were exposed to a chemical that damages DNA, the cells of people taking cat's claw had less DNA damage and repaired it better. No harmful effects showed up in symptoms or blood tests. The study was very small and didn't test whether this prevents or treats any disease.[3]Study

    Technical detail: C-Med-100 extract; DNA damage induced by hydrogen peroxide; p < 0.05 versus non-supplemented controls.

In short

May worsen autoimmune diseases and slow blood clotting; some studies suggest it's unsafe in pregnancy.

Sources

  1. [1] WHO monographs on selected medicinal plants, Volume 3 — "Cortex Uncariae" monograph — World Health OrganizationGovernment health agency
  2. [2] Cat's Claw: Usefulness and Safety — National Center for Complementary and Integrative Health (NIH)Government health agency
  3. [3] DNA repair enhancement of aqueous extracts of Uncaria tomentosa in a human volunteer study · DOI: 10.1078/0944-7113-00045Peer-reviewed study

This information is educational and traditional in nature, and is not a substitute for professional medical advice. Unfamiliar word? See what these words mean.