Are We Overusing Antibiotics?

In the mid-1970s, I was asked by the Animal Health Institute to propose a study which would address the possible human health consequences of providing antibiotic-laced feed to farm animals. The resulting prospective study (Levy et al., 1976) examined the effects of providing subtherapeutic levels of an antibiotic as a growth promoter to animals on the intestinal flora of people and animals.

We raised 300 chickens from the day of hatching to full-grown hens and roosters, placed them in cages, and…