Book excerpt: This book investigates the widespread historical belief that the consumption of arsenic, generally known to be a deadly poison, is beneficial to one's health. Accordingly, many "poison eaters" were found among the Austrian rural population in the nineteenth century. What they were ingesting was white (arsenic trioxide) or yellow arsenic (arsenic trisulfide). It was produced by roasting arsenic-containing minerals. Arsenic eaters were robust persons, and usually of the lower class of society, wood cutters, charcoal burners, stablemen, foresters, etc. They ingested arsenic to be 'strong and healthy': to look rosy, to resist fatigue or to strengthen their physique: "See how strong and fresh I am, and what an advantage I have over you all! In times of epidemic fever or cholera, what a fright you are in, while I feel sure of never taking infection." Though being a popular custom among hard working people, arsenic eaters were very anxious to conceal the fact, particularly from medical men and priests. It was also believed that once a person became an arsenic eater, he can never stop the habit. To do so would bring rapid decline in health, leading inevitably to death.