The Sego, or King Sago Palm is native to Japan and China. It grows on hillsides in thickets on small islands on the Japanese chain of islands. They have a thick 2 foot diameter trunk that reproduces through offsets or suckers that grow at the base of the plant. There are several stands that are protected in nature now, but most of these palms grow in cultivation.
According to the ASPCA this plant is toxic to dogs, cats, and horses. It is also highly toxic to humans! Cycasin (a toxic glycoside) may cause these symptoms with exposure: vomiting, diarrhea, weakness, seizures, liver failure, or hepatotoxicity characterized by icterus (jaundice), cirrhosis (scarring of the liver, and poor functioning), and ascites (fluid in the peritoneal cavity). The pet may appear bruised, have nose bleeds (epistaxis), melena (blood in the stool), hematochezia (bloody straining), and hemarthrosis (blood in the joints). This plant has great potential as a toxin with pets, as they find the flavor enticing. Every part of this palm has some Cycasin, but it is especially concentrated in the seeds.
Even though there is toxicity present in every part of the plant, it was still used for food and medicine. In folk medicine the leaves were used in the treatment of cancer and specifically hepatoma (liver cancer). The seeds were utilized to help rheumatism, and an extract was used to inhibit the growth of cancer tumors.
The seed is also eaten raw or cooked! The seed can be dried and ground to be added to rice which is fermented into date miso. The pith of the trunk is dried and powdered then utilized to make dumplings, which are very sustaining.
There are methods of treatment of this plant and its seeds that are very exacting to make it palatable and not toxic! To try and use this plant at home is ill advised!!