Hi! Acidophilus, also known as lactobacillus acidophilus, is a bacteria that is commonly found in the digestive tract; for women, it is also found in the vagina. Considered a good bacteria, acidophilus produces vitamin K, which helps in forming blood clots, as well as lactase, which breaks down lactose in the body. This probiotic also creates microbial substances that fight off bad germs and bacteria in the body. Acidophilus is a living organism and can be purchased in both capsule and pill form. As a probiotic, it may be used to prevent and treat anti-biotic diarrhea, yeast infections and urinary tract infections. Other ways it can help the body are by protecting against colon cancer and the adverse effects of chemotherapy and radiotherapy. Furthermore, they can be taken as a preventive against food poisoning when traveling. Acidophilus can also be found in yogurt, and other products.