It’s been a long time since aspirin was limited to curing common aches and pains. Recent research positions the anti-inflammatory drug as a way to prevent, as well as treat, general health (and beauty) concerns. Unfortunately, a new study published in the journal Heart found these benefits vary based on a person’s age.

Researchers from The Netherlands and Boston looked specifically at 27, 939 healthy women ages 45 and older, and whether or not an alternate-day, low dose of aspirin affected their risk for diseases, like cancer, cardiovascular disease, and gastrointestinal (GI) bleeding. Women were randomly assigned to take 100 milligrams of actual aspirin or a placebo for 10 years. Despite aspirin being associated with a modestly decreased 15-year risk of disease, the results suggested otherwise.

Well, let’s back up for a minute. Women taking aspirin in the study were found to be at a lower risk for certain diseases — but not by a significant amount. And it wasn’t enough to outweigh the second major result: two thirds of women taking regular aspirin experienced GI bleeding.

GI bleeding can come from several areas in the body, including the esophograus, stomach, small intestine, colon, and rectum. The National Institutes of Health reported the amount of bleeding varies on the body part it’s occurring, however, “black or tarry stool” and “dark blood mixed with stool,” occur universally. Worse yet, this type of bleeding is usually symptomatic of another disease, like ulcerative colitis, Crohn’s disease, and cancer.

The chance of bleeding increased as women aged, but so did aspirin’s ability to lower risk for bowel cancer and cardiovascular disease. The results then suggest women ages 65 and older benefit more from an alternate-day, low dose of aspirin for added health benefits.

There is, of course, a catch.

“Despite these findings, the role of aspirin in primary prevention remains unclear, as it is uncertain whether the combined benefits for cancer and cardiovascular disease outweigh the increase in major bleeding events,” the researchers wrote. “As treatment effect may be determined by multiple patient characteristics, using models to predict treatment effect for individuals could help to select patients for aspirin treatment.”

Source: van Kruijsdijk RCM, et al. Individualized prediction of alternate-day aspirin treatment effects on the combined risk of cancer, cardiovascular disease and gastrointestinal bleeding in healthy women. Heart, 2014.