View photos of the medicinal plant Osmorhiza berteroi (Sweet cicely), profiled in Medicinal Plants of the Western Mountain States.

A passage from Medicinal Plants of the Western Mountain States:

After holding the strongly made tea in the mouth for 10–15 seconds a slight numbing quality should be sensed. This same sensitivity reducing effect (though not as strong as Kava’s) is responsible for its soothing gastrointestinal quality.