A spoonful of sugar may help the medicine go down, but a growing body of research casts the sweet stuff as a bitter pill. While our ancestors had access to sugar only by way of fruits, the purified stuff has become an alarmingly major part of the Western diet. It’s in a great many processed foods—dessert items or otherwise—and people use and abuse sugar to the point that some nations are trying to control it like tobacco or alcohol. (Before passing its “fat tax,” Denmark imposed high tariffs on sugary goods.) Even sugar substitutes are coming under fire: A recent study reported a link between artificial sweeteners and the risk of metabolic disorders and diabetes, and some of you may recall a period when saccharin-sweetened goods were suspect because the substance caused cancer in lab animals. But perhaps one of the strangest sweeteners was lead-based—and as you might expect, its ingestion carried serious consequences.

Lead acetate, also known as sugar of lead, is a salt that (ironically) has a sweet flavor—a fairly unusual quality in poisons, which are more likely to taste bitter, signaling to the taster that they are unsafe for consumption. The ancient Romans used the compound—which they called sapa—to sweeten wine, and the aristocratic segments of the population could toss back as much as two liters a day (about three bottles’ worth, although wine was usually diluted with water). There is debate as to whether the wine alone could have produced the traditional physiological effects of lead poisoning, such as organ failure, infertility and dementia—the little things that help facilitate the fall of an empire.

This is not to say that sugar of lead can’t be lethal. When Pope Clement II died in 1047, no one was exactly sure what killed him, but a 1959 examination of his remains clearly indicated lead poisoning. No one knows for sure if it was accidental or intentional, but one thing was for certain: the man liked his wine, especially those from his native Germany which were sweetened in the ancient Roman manner. And while a number of theories have cropped up concerning Ludwig van Beethoven’s cause of death, ranging from syphilis and coronary disease to lupus, lead poisoning by way of wine has also been suggested as a contributing factor to his demise.

All that said, sugar of lead is probably best left to its modern application: hair coloring products, which, incidentally bear warning labels that this substance is contained therein.