As a child growing up in the Soviet Union, Maria Pirogovskaya recalls that her mother would often come back from the pharmacy with a “wholesome and healthy treat” for her daughter: a “candy bar” called Hematogen. Officially produced as an over-the-counter supplement to treat anemia, which affects nearly a quarter of all humans but is especially prevalent in young children, it was made with beet sugar, condensed milk, and syrup , so Pirogovskaya gobbled it up. It was basically the Soviet equivalent of gummy vitamins , although its texture was more like a Tootsie Roll. “In school,” adds Pirogovskaya, “I bought it every time I passed near a pharmacy and had pocket money.”

Unlike modern America’s sweet supplement treats, though, the Hematogen that Pirogovskaya grew up gobbling wasn’t made with vitamins and minerals isolated from natural products or produced synthetically in a lab. (It’s also not tied to the oral iron tablet Hematogen FA found in the US market.) Its iron, which prevents anemia, came from black food albumin—a technical term for blood. Specifically, Soviet manufacturers produced Hematogen bars such that each was at least 5 percent cow’s blood.

Hematogen wasn’t a rare product or a brief experiment. By most accounts, it was a fixture in Soviet pharmacies for decades, right up until the collapse of the USSR—and in Soviet childhoods. Even today, it is still widely available throughout the former Soviet Union, albeit not as ubiquitous as it was a few decades ago. (Modern manufacturers and retailers now sell varied types of Hematogen not just for anemia, but for everything from improved concentration to lustrous skin to protection from the common cold.)

“You can actually go and buy it right now in New York,” says Anastasia Lakhtikova, co-editor of the forthcoming academic tome Seasoned Socialism: Gender and Food in Late Soviet Everyday Life—provided you know the right place to look in Russian markets.

Researchers across Europe created a host of blood-based products, like Hematopan, “blood powder sweetened with licorice,” and Haemosan, a “drink made of blood protein, lecithin, and calcium glycerophosphate.”

This may sound like one of the many bizarre consumer goods relics of the Soviet era—a product born of thrift, pragmatism, and centralized, totalitarian production and distribution. But the roots of Hematogen predate the USSR. For starters, most human cultures have a long culinary tradition of consuming animal blood; Russia, notes Adrianne Jacobs, a contributor to Seasoned Socialism, has long trucked in blood sausages. Some of humanity’s historic relationship with blood-based foods stems from histories of scarcity and the head-to-hoof ethos that can result from them. But much of it also stems from our longstanding realization that, as Jacobs puts it, “blood is incredibly nutritious”—packed with protein, vitamins, and minerals, and containing less cholesterol than eggs.

Pirogovskaya, today a historian of Russian food and medicine at the European University at St. Petersburg, adds that thanks to rising awareness of and interest in public health and food chemistry during the 19th century, “European physicians and manufacturers were seduced by the idea of creating non-perishable and highly nutritious foods.” They fiddled with everything from cocoa to milk to yeast, producing powdered forms and extracts of all manner of products. They turned their eyes to blood as well, hoping to distill its nutritional value into shelf-stable, palatable forms. (Raw blood spoils incredibly quickly and easily, especially during industrial animal slaughter.) Pirogovskaya notes that researchers across Europe created a host of blood-based products, like Hematopan, “blood powder sweetened with licorice,” and Haemosan, a “drink made of blood protein, lecithin, and calcium glycerophosphate.” Hematogen, according to the Russian newspaper Pravda, originated in a Swiss doctor’s lab as part of this late 1800s modernist food craze.

The idea of harnessing blood in a mass-produced, easy-to-store, and sweetened form to treat anemia wasn’t a crazy idea, says hematologist Thomas DeLoughery. To this day, doctors recommend iron supplements to those at risk of a deficiency. But iron tablets aren’t always very palatable, and most people don’t absorb the nutrients in them well; DeLoughery and others usually co-prescribe vitamin C supplements to help their patients absorb supplemental iron.