A variety of plants and seeds, some of which are used for therapeutic and nutritional purposes, can cause neurotoxic symptoms. The ingestion of the green or ripe fruit of the Karwinskia humboldtiana (buckthorn), a bush known in Mexico as coyotillo or tullidora, causes a flaccid, symmetric, progressive, and ascending palsy of the lower limbs, which, in severe cases, can cause bulbar palsy and death. The neurologic symptoms are similar to those of poliomyelitis, Guillain-Barré syndrome, and other polyradiculoneuritis syndromes, for which it is often mistaken. The clinical diagnosis of intoxicated patients can be difficult without a history of the fruit ingestion. We present a report of three siblings with buckthorn intoxication.