Probiotics are "good" bacteria that live in your gut and aid in digestion. The World Health Organization says probiotics are "live microorganisms, which, when administered in adequate amounts, confer a health benefit on the host." You'll find probiotics in fermented foods and supplements -- but pay attention to the strain and species of microorganism -- because some types, such as Lactobacillus acidophilus and Bifidobacterium bifidus, are more useful than others.
Taking probiotics is generally regarded as safe, but you should always consult your physician before adding any type of supplement to your diet.
Eat more yogurt and kefir. Dairy foods are easily fermented, also known as cultured, and contain Lactobacilli, a type of bacteria that might help stop diarrhea and treat yeast infections. According to the Harvard Medical School, "Probiotic treatment that restores the balance of microflora may be helpful for such common female urogenital problems as bacterial vaginosis, yeast infection and urinary tract infection." Dairy is an excellent environment for bacteria because the live microorganisms feed on lactose, a naturally occurring sugar in dairy products. Yogurt can be eaten or inserted directly into the vagina, but this folk remedy shouldn't take the place of conventional treatment.
Add fermented vegetables to your diet. Sauerkraut, kim chi and pickles contain live bacteria -- providing they have not been pasteurized. Any heat treatment will kill the microorganisms. Read labels carefully and choose products that say "raw," "unpasteurized" or "contains live cultures." Beverages such as kombucha -- a fermented tea, and raw apple cider vinegar also contain live cultures.
If you can't get the bacteria you need from your diet, you can take a probiotic supplement. The probiotic supplements contain dormant bacteria, but are still live. If you choose to take supplements, always check the expiration date, as the bacteria become less effective over time. Supplements can be extremely effective when traveling and can help you avoid traveler's diarrhea. Probiotic supplements are not regulated by the FDA as drugs, so look for a reputable brand that lists the different species and number of live organisms contained -- look for a number in the billions.