FYI:<br/><br/>here is the info I found on rat poison used in the "old west"<br/><br/><br/>In the Old West, methods of rat control (cats and traps, aside) relied heavily upon poisoning. The unpleasant taste of early poisons had to be disguised by combining them with various foods, including meat or grain. If a rat survived the first bite of such a mixture, it would usually not return for a second bite, thereby, becoming “bait-shy.” Rat survivors are so smart that they have been known to urinate or defecate upon some poisonous baits, undoubtedly to warn other rats to stay away. To avoid the problem of bait shyness, historical rat poisons had to kill after just one bite. Consequently, these extremely potent poisons were also very dangerous to pets and humans, especially children.<br/><br/>Effectively and historically useful, but now obsolete, overly dangerous poisons include compounds like arsenic (ratsbane), strychnine, thallium sulfate, barium carbonate and phosphorus paste.<br/><br/>No less lethal, an Old West standby, red squill, is still utilized today, but is somewhat safer for a very interesting reason. Hendrickson indicates: Red squill, an ancient rat poison, known to rat killers since at least 1500 B.C., is a flowering plant with large bulbous roots that are cut into slices, dried in the sun and then ground into various preparations, including a digitalis-like medicine that kills the rat by paralyzing its heart.<br/><br/>Very bitter and certain to cause bait shyness, red squill naturally causes emesis (vomiting), a characteristic that makes it somewhat safer as a rodenticide than other compounds that do not have this effect. Interestingly, “rats, like most rodents, and unlike humans, are unable to vomit and are not protected by red squill’s emetic quality.”