In this issue, Larson and colleagues (4) performed a well-designed, labor-intensive, randomized, double-blind trial comparing symptom rates among families with at least 1 preschool-age child who used handwashing and household-cleaning products with or without antibacterial ingredients. The intervention households received a kitchen cleaner (with a quaternary ammonium compound), laundry detergent (with oxygenated bleach), and liquid handwashing soap (with triclosan). Control households received identically packaged products without the antibacterial ingredients. Both groups received the same liquid dishwashing detergent and bar soap, without antibacterial ingredients. The households were followed for 48 weeks, with active monthly surveillance for adherence to product regimens and infectious disease symptoms (vomiting, diarrhea, fever, sore throat, cough, rhinorrhea, skin infection, and conjunctivitis). No significant differences between the 2 groups were found in reports of symptoms, which included rhinorrhea (26.8%), cough (23.2%), fever (11%), sore throat (10.2%), vomiting (2.6%), and diarrhea (2.5%). Fewer than 1% of the households reported any skin symptoms. Within most subgroups, such as young children, children attending day care, and persons working outside the home, no differences were found between the 2 groups. Interestingly, persons with chronic disease or poor health in the antibacterial product group were more likely to have fever, rhinorrhea, and cough.