Antibiotics

Most of the world’s antibiotics go to farm animals

By WhyStopHarmingAnimals.com

Most of the antibiotics used on Earth are not given to people[1][2]. Van Boeckel and colleagues, writing in Science in 2019, found that 73% of all antimicrobials sold worldwide are used in animals raised for food[1]. They noted that studies have increasingly linked this use with the rise of antibiotic-resistant infections in animals and in humans[1]. Those infections already kill more than a million people a year[6].

Where the drugs go

Our World in Data reaches the same range by another route[2]. Weighting use by the mass of animals and people[2], it estimates about 85,000 tonnes a year go into farm animals, against about 35,000 tonnes in people, which puts the farm share at around 70 to 73%[2].

The pattern holds in the United States, and it involves the drugs doctors depend on. About 70% of medically important antibiotics sold in the U.S. are for animals rather than humans, as Scientific American has reported[3]. These are the same classes of drug used for pneumonia, sepsis and surgery. The FDA’s summary of 2024 sales found that sales of medically important antimicrobials for food-producing animals rose about 16% in a single year, from 2023 to 2024, to about 7.1 million kilograms[4]. Pigs and cows took most of it.

Why farms use so much

Factory farms pack animals so closely that infection is built into the system. Cows, pigs and chickens are kept in crowded barns where disease spreads fast, and antibiotics are mixed into their feed and water so the barns do not collapse into outbreaks. In the U.S., the use of antibiotics to make animals grow faster was removed from drug labels, but the crowding stayed, so the drugs kept flowing under the name of prevention.

Every dose given to a crowded herd or flock favors the bacteria that survive it. The World Health Organization lists antimicrobial resistance among the top global public health threats[5] and says overuse in people and in animals raised for food both select for resistant bacteria[5]. Those bacteria do not stay in the barn. They travel on meat, in manure and water, and with the workers who handle the animals, and from there into homes and hospitals.

The death toll

A study in The Lancet, pooling data from around the world, counted about 1.27 million human deaths in 2019 caused directly by bacterial antimicrobial resistance[6], and about 4.95 million associated with it[6]. The first number counts people who died because the drugs failed; the second counts people who died with a resistant infection that may or may not have been the main cause. In the United States, the CDC’s 2019 threats report found more than 2.8 million antibiotic-resistant infections a year and more than 35,000 deaths as a result[7].

The forecasts are worse. A 2024 study in The Lancet by Naghavi and colleagues projected about 1.91 million deaths a year directly caused by resistance by 2050[8], and about 8.22 million associated with it[8]. From 2025 to 2050, that adds up to about 39 million deaths caused directly[8] and about 169 million associated[8]. The UK’s O’Neill Review on Antimicrobial Resistance, published in 2016, projected 10 million deaths a year by 2050 without action[9], and named farm-animal antibiotic use as one of the drivers[9].

What the numbers do and don’t show

The 73% figure is an estimate of sales[1] by weight, and tonnage alone does not show which uses cause the most resistance. Overuse in human medicine is part of the problem too, as WHO says[5]. The death tolls cover resistance from every source, and none of these studies works out what share traces back to farms. The 2050 forecasts depend on assumptions about how resistance and treatment will change, which is why the Lancet and O’Neill projections differ by millions of deaths a year[8][9].

The share is still hard to explain away. When nearly three-quarters of a medicine goes to animals[1][2] kept in conditions that make them sick, that use is a large part of why the medicine keeps failing. A vegan diet does not need those barns, so it does not need that dosing. We harm ourselves by harming animals, and antibiotic resistance is one of the clearest ways the harm comes back to us.