The World Health Organization is warning that bacteria are becoming so resistant to antibiotics that even simple injuries and diseases could become deadly.
WHO Director General Margaret Chan said the changes in bacteria could lead to "the end of modern medicine as we know it."
She said it's becoming harder and harder to develop new antibiotics.
"We are losing our first-line anti-microbials," Chan said during a recent conference on combating anti-microbial resistance.
"Replacement treatments are more costly, more toxic, need much longer durations of treatment, and may require treatment in intensive care units," she added.
Chan also warned that something as simple as strep throat or a child's scratched knee could actually lead to deaths.
"At a time of multiple calamities in the world, we cannot allow the loss of essential anti-microbials, essential cures for many millions of people, to become the next global crisis," Chan said.