A clear link exists between taking antibiotics for six months and developing colorectal cancer in the next five to 10 years, report researchers from Umea University, in Sweden. By comparing the records of 40,000 Swedish cancer patients to 200,000 people without cancer, they found that taking antibiotics for at least six months increased the risk of cancer by 17 percent in the ascending colon, the first part to be reached by food after the small intestine. However, no increased risk was found for cancer in the descending colon. Those taking the most antibiotics had the greatest risk, but even a single course was associated with a small, but statistically significant risk increase. “While in many cases antibiotic therapy is necessary and saves lives, in the event of less serious ailments that can be expected to heal anyway, caution should be exercised,” says Umea University researcher Sophia Harlid, Ph.D.