Ingestion of the green or ripe fruit of Karwinskia humboldtiana (a bush known as buckthorn, coyotillo, or tullidora). Causes a flaccid, symmetric, progressive, and motor ascending palsy of the lower limbs. In severe cases, can cause bulbar palsy and death. Clinically, the symptoms are similar to Guillain-Barré syndrome. In many patients, the plant toxin can be detected.