A study in the journal Gut found women who took oral antibiotics for at least two weeks in their 20s through 50s increased their risk of colon polyps in their 60s, compared with not taking the drugs for extended periods of time.

“This suggests that alterations in the naturally occurring bacteria that live in one’s intestines caused by antibiotics might predispose individuals to colorectal cancer,” said lead researcher Dr. Andrew Chan.

Although the study calls two weeks of antibiotics anytime in a single block from basically young adult to middle-age an “extended” exposure, obviously many people are at risk. More research is under way.