Rotavirus-induced diarrhea is a common infection that results in the death of nearly 500,000 children annually. Currently, no large-scale preventative treatments or vaccines exist. Because some whey protein concentrates (WPC) were shown to contain bioactive ingredients that may activate immune cells and/or prevent infection, the current study was conducted to assess whether the proprietary WPC IMUCARE (WPC-IC) could protect against rotavirus. Suckling BALB/c mice were treated by gavage once daily with WPC-IC or with the control protein bovine serum albumin from the age of 9 to 17 d, and were infected with murine rotavirus at the age of 11 d. Disease symptoms were graded as mild, moderate, or severe, and viral shedding was measured in fecal samples during the postinfection period. Severe diarrhea occurred in 63% of control mice; this was significantly reduced to 36% in WPC-IC-fed mice. Severe diarrhea occurred for a 4-d period in the control group but only for a 2-d period in the WPC-IC group. Although the mean viral load per mouse did not differ between the groups, the proportion of mice shedding high levels of the virus in the feces postinfection was significantly lower in the WPC-IC group on d 13, 16, and 17, and significantly higher on d 14. Rotavirus-specific antibody levels in serum and gut fluid did not differ between groups. Thus, prophylactic treatment with WPC-IC may reduce rotaviral disease by decreasing the prevalence of severe diarrhea and by decreasing the time period during which severe symptoms and high viral shedding occur.