Last Updated: September 28 2022

Uncaria rhynchophylla (Gou-Teng or Chotoko) is an antiepileptic eastern medicine and major component of 'Yokukansan' for the treatment of agitation in elderly persons. It appears to be neuroprotective, anticonvulsive, and has antipsychotic properties like Aripiprazole.

Gou-teng is most often used for


Uncaria rhynchophylla (not to be confused with Uncaria Tomentosa) is a traditional chinese medicine and Japanese medicine that is used for the treatment of hypertension, convulsive disorders (epilepsy), and for various head ailments such as headache or dizziness. It contains a variety of alkaloid structures, most notably the one named after it (Rhynchophylline) and a potent drug-like alkaloid with the acronym of GME (Geissoschizine methyl ether). It is a component of the popular japanese medicinal formula known as Yokukansan, where it alongside glycyrrhiza uralensis (licorice) seem to mediate the neuroprotective effects.

Studies that use oral ingestion of the herb or isolated alkaloids are only in the animal phases of research at this point in time, but it appears that GME has antipsychotic properties very similar to Aripiprazole (pharmaceutical) on the serotonin and dopamine receptors. The influence on the serotonin receptors also confers some anxiety reducing properties, and can reduce social aggression (thought to be the reason why Yokukansan reduces agitation in elderly persons with dementia).

There is also a neuroprotective effect that is mostly based on preventing the brain's support cells (glial cells, which support the neurons) from activating in response to inflammation. This antiinflammatory effect in the brain appears to underlie anti-epileptic properties with oral ingestion of the herb.

Beyond that, there is potential for this herb to reduce blood pressure secondary to activating nitric oxide signalling but this has not yet been investigated in living systems.

What else is Gou-teng known as?
Note that Gou-teng is also known as:
  • Uncariae Uncis Cum Ramulus
  • Choto-ko
  • Choto-san
  • Pulvis Uncariae
  • Diao-teng-san
  • Gou-teng
  • Uncaria Rhynchophylla
Gou-teng should not be confused with:
  • Cat's Claw (Uncaria tomentosa or guianensis)
Dosage information

There is currently no evidence in humans to recommend an ideal human dose, but based on the rat studies conducted noting efficacy with the water extract at 250-1,000 mg/kg oral intake a preliminary guess at the dosages would be:

  • 2,700-11,000 mg for a 150lb person
  • 3,600-14,500 mg for a 200lb person
  • 4,500-18,000 mg for a 250lb person

The formulation known as Yokukansan (one serving is 20.5 grams) which is given to humans contains three grams of uncaria rhynchophylla, and this may be a prudent starting dose even if using it in isolation.

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