Beans give most people uncomfortable flatulence, but some legumes can be real killers.

Seven people were recently hospitalized after being around a suspicious vial of white powder in a Las Vegas motel room, according to an Associated Press (AP) story published today. The man found in the room with the vial even slipped into a coma.

The culprit? FBI officials have fingered the deadly poison ricin, which “… is made from the waste left over from processing castor beans. As little as 500 micrograms, or about the size of the head of a pin, can kill a human” according to the Centers for Disease Control (CDC), the AP author wrote. Terrorism isn’t suspected.

Castor plants grow up to 15 feet (4.5 meters) in height, and are thought to have originated in Africa. Hundreds of millions of tons of the oil from their beans is extracted each year, and is used in everything from food additives, laxatives and pharmaceutical drugs to animal repellant, mold inhibitors and food packaging.

According to the CDC, ricin extracted from the bean’s leathery casing kicks in about 6 to 8 hours after being inhaled or swallowed. Once in the body, the toxin begins to shut down protein-making machinery in the body’s cells, eventually killing them.

If inhaled, severe flu-like symptoms appear in about 8 hours, followed by bluing of the skin and excess fluid in the lungs. Those unfortunate enough to swallow the compound suffer severe diarrhea, dehydration, low blood pressure, hallucinations, and even seizures.

No antidote yet exists for ricin, and it takes about three to five days to recover naturally — so don’t go sniffing any suspicious white powders around town.