It has live naturally - occurring microorganisms that promote a healthy digestive system and strong immunity against diseases. (topdogtips.com)
That's why they need a series of vaccinations, usually starting at six to ten weeks of age, to stimulate their own immunity against disease. (animals.howstuffworks.com)
If you've done your research, you know that antioxidants help the body build immunity against diseases. (thefashionablehousewife.com)