Cat’s claw (Uncaria tomentosa) is a woody plant native to the Amazonian and Central American rain forests. Its name comes from the hook-like thorns which resemble a cat’s claws. South Americans have been using Cat’s claw bark and root as a treatment for arthritis for decades, and treating intestinal problems such as gastritis, colitis, and stomach ulcers.

Cat’s claw is used most often to boost symptoms of both osteoarthritis and rheumatoid arthritis.

This is often used for numerous digestive system disorders like large bowel swelling and pain (inflammation) (diverticulitis), lower bowel inflammation (colitis), inflammation of the stomach lining (gastritis), stomach ulcers, hemorrhoids, and leaky bowel syndrome. 

Many people use cat’s paw as shingles (caused by herpeszoster), cold sores (caused by herpes s) for viral infections), and AIDS.

Cat’s claw is often used for chronic fatigue syndrome (CFS), wound healing, infections, Alzheimer’s disease, asthma, hay fever, cancer, a rare form of brain cancer named glioblastoma, gonorrhea, dysentery, birth control, bone pain, and “cleansing” the kidneys.

Health Benefits of Cat’s Claw

Several early studies have indicated that the cat’s claw has beneficial immune-modulating and antioxidant effects in treating arthritis and other health conditions. While these arguments being expansive, no existing evidence supports its use.

According to the ABC Medical Guide to Herbs, this has not prevented customers from purchasing the supplement which was ranked 25th in herbal remedy sales in 2000. (R)

Here’s what the new report says:

Boost Your Immune System

Cat’s claw may support the immune system, probably helping you more efficiently combat infections.

A small study of 27 men showed that eating 700 mg of cat’s claw extract for 2 months increased the number of white blood cells involved in infection control. (R)

Similar findings were reported in another small study in four men given the cat’s claw extract for six weeks.(R)

Cat’s claw continues to function by stimulating the immune system and relaxing an overactive body. The anti-inflammatory effects may be responsible for its immune benefits. (R)  (R)

Given these positive findings, there is a need for further studies.

Lyme Disease

A special type of cat’s claw, known as samento, is thought to help in Lyme disease care. Many of the proof is based on test-tube experiments where samento was better able to neutralize the causal bacteria (Borrelia burgdorferi) than the doxycycline antibiotics.(R)

Proponents suggest that samento will “improve” the immune system more effectively than the normal cat’s claw, as it is devoid of a compound called tetracyclic oxindole alkaloid.

It is unclear if the same impact will be seen outside the test tube. To date, health claims are mostly unfounded in their veracity, and there is no proof that samento can either reduce the frequency of Lyme disease or shorten its duration.


Osteoarthritis is the most common joint condition in the United States, causing painful and rigid joints.(R)

In one study, taking 100 mg of cat’s claw extract for 4 weeks in 45 people with osteoarthritis in the knee resulted in decreased pain during physical activity. No side effects have been reported.

Nevertheless, there was no improvement in either rest pain or knee swelling. (R)

A supplement to cat’s claw and maca root a Peruvian medicinal plant decreased pain and stiffness in persons with osteoarthritis in an eight-week trial. Additionally, pain medication was required less frequently by the participants. (R)

Another study tested a routine mineral supplement in humans with osteoporosis alongside 100 mg of the cat’s claw extract. Joint pain and function increased after 1–2 weeks compared with those who did not take the supplements. (R)

And the gains were not maintained after eight weeks.

It should also be noted that in studies that test multiple supplements at once, it can be difficult to determine the specific behavior of the cat’s claw. 

Scientists claim cat’s claw will relieve symptoms of osteoarthritis because of its anti-inflammatory properties. (R)


Some early test-tube experiments have indicated that antitumor properties could be present in the POA found in cat’s claw. 

POA is known to be harmful to particular cells of cancers and to have less effect on the healthy cells that are normally affected by chemotherapy.

Although the cytotoxic (cell-killing) effect was close to that of the Cytoxan (cyclophosphamide) drug, the dosage required to achieve this effect would probably be excessive in humans. Still, the result indicates a possible new path for the production of cancer drugs. (R)

Cat’s Claw Side Effects

While side effects of cat’s claw are rarely recorded, there is currently insufficient information available to assess its overall health.

If ingested in large quantities, the high levels of tannins in cat’s claw can cause some side effects— including nausea, stomach pain, and diarrhea. (R)

Bleeding disorders: Cat’s claw can delay coagulation of the blood. There is concern that cat’s claw in humans with bleeding disorders that increase the risk of bruising or bleeding. (R)

People taking other drugs. Because cat’s claw can converse with other medications like those for blood pressure, cholesterol, cancer, and blood clotting, you should speak to your doctor before you take it. (R)

Surgery: There is a risk that cat’s claw may make it difficult to regulate blood pressure during surgery. Stop taking cat’s claw at least two weeks before a scheduled operation.

Pregnant and breast-feeding: There is some fear that during breastfeeding, when taken by mouth, cat’s claw is POSSIBLY Unhealthy. Not enough information is available on the safety of cat’s claw during breast-feeding.

Cat’s Claw Dosage

Scientific work has tested the following doses: 

WHO claims, however, that a typical daily dose is 20–350 mg of dried stem bark for extracts or 300–500 mg for capsules, taken in 2–3 separate doses all day long (R).

Researchers have used 60 and 100 mg daily dose of cat’s claw extract to treat rheumatoid arthritis and knee osteoarthritis, respectively. (R)

One possible risk is that the FDA does not closely control certain herbal supplements— including the cat’s claw. Hence, purchasing the cat’s claw from a trustworthy manufacturer is better to reduce the possibility of contamination.

The Bottom Line

Cat’s claw is a popular herbal supplement that comes from tropical vineyards.

While there is limited research to support many of its supposed health benefits, some evidence suggests that cat’s claw may help boost your immune system and ease osteoarthritis and rheumatoid arthritis symptoms.

Since safety and dosage recommendations have not been established, it may be best to consult your doctor before cat’s claw is taken.