You probably know that an antibiotic is meant to kill bacteria in your body. Well, a probiotic is meant to deposit bacteria. Your digestive system is full of "good" bacteria that help your body break down your food so that you can absorb the nutrients. If you don't have a plentiful supply of these bacteria, you run into problems. (Taking antibiotics are one way to kill them off.)You can get probiotics like as acidophilus and bifidus in cultured foods, such as yogurt or kefir. If you are deficient in them, I recommend you get a good brand of probiotic supplement. You have to reach critical mass before you will notice the difference, so go for one that has 30 billion to start with. After a month, cut back to 15 billion and see if it still works.That said, I have not noticed any difference in my C or D as a result of taking probiotics. I do, however notice a big difference in vaginal yeast infections and white tongue coating. Other people may have a different experience.L