With two ricin-laced letters confirmed to be sent to New York City Mayor Michael Bloomberg and his gun rights group, plus another to President Obama -- all postmarked from Shreveport -- folks are asking just how dangerous ricin is. KEEL News asked Louisiana Poison Control Director Mark Ryan.

"Ricin itself is a substance that's found naturally-occurring in castor beans from a castor plant. That plant grows wild across the country. It's very common here in our area," Dr. Ryan says. "Ricin really becomes a problem, and it's a very harmful substance, when it gets inside the body."

Dr. Ryan says if your skin is exposed to it, you might notice a little pain and redness.  Washing the area with soap and water will get rid of the problem.  But if you touched ricin, then picked up food or put your hands to your mouth, the poison could get into your system.

"We have children, animals that swallow a couple of castor beans.  That's really not enough to cause serious issue in most cases, especially if you swallow the beans whole. They've got a tough outer covering, kind of a shell, on them, not digested easily," Dr. Ryan says.  "So that's not a big concern for us. But if you do swallow ricin itself, vomiting and diarrhea may be really severe." That, in turn, could cause you to lose fluids, and become seriously dehydrated.

Another problem with ricin is taken up by organs, specifically the liver, kidneys and spleen.

"What it does is it blocks the production of proteins," Ryan says.  "All of our cells need protein. So if they don't get that protein, they die.  So ricin symptoms usually start within about three or four hours, and a person can die within 36, 72 hours."

Dr. Ryan says there are numerous common substances made from castor beans -- like Castor Oil -- that aren't harmful.  Listen to the rest of our interview here: