"Lactobacilli, for example, are more affected by the broad-spectrum drugs," Dr. Kozyrskyj said, referring to the beneficial bacteria contained in yogurt.

SMATs are new, broad-spectrum drugs that unify antibacterial, antiviral and anti-malarial activities into a single therapeutic that offers substantial cost benefits and logistic advantages for physicians and the military.

"There's a great deal of optimism that we would be able to target drugs to people, instead of using broad-spectrum drugs, and that we would be able to target dosage levels," said Mark A. Rothstein, director of the Health Law and Policy Institute at the University of Houston.