Lump med side effects with bacterial infections, viruses, parasites and stress and you’ve got a nightmare combo for diarrhea, which hits about 70% of people with HIV at one time or another. It’s long been assumed that milk products intensify the problem, so many sufferers try a dairy-free diet. But that carries its own risks, such as weak bones (too little calcium) and weight loss—both of which are already exacerbated by HIV. Now, a Canadian study says positive people—even those with lactose intolerance—can drink milk without heightened gastric distress.

People in the study had chronic diarrhea (at least three bowel movements a day over the previous month). Some 80% of the 49 participants were on HIV meds, and none had parasites or other bowel-loosening infections (so it’s still unclear what effect milk will have if that’s the source of your runs); ten were lactose-intolerant. They drank a cup of milk a day—lactose-free one day, low-fat regular another—and neither kind increased their diarrhea. Study author Jill Tinmouth, MD, of the University of Toronto points out that dairy intake should be moderate—about eight ounces every eight hours—and adds, “I am encouraging my positive patients with diarrhea to stop avoiding dairy.” It does a body good.