Some important bugs live in your body. If they didn't, you'd be in trouble. Think of Lactobacillus acidophilus, bifidus, bulgaricus and similar organisms as the body's good bacteria (also called probiotics). They grow in the vagina and intestines, where they improve digestion, produce vitamins and help counter Candida overgrowth (the cause of thrush and other yeast infections). They may also help prevent other intestinal infections. Unfortunately, they're often killed by antibiotics, so nutritionists -- but too few doctors -- urge anyone taking these drugs to supplement with probiotics.

Nutrition counselor Jennifer Jensen of Santa Monica, California recommends a liquid probiotic mix for oral thrush: Swish, gargle, swallow. "I had one client whose thrush cleared up in a day, and most people clear it within two or three days. It turns black, then falls off," she says. For vaginal yeast infections, Jensen advises using probiotic suppositories.

These good bacteria can also help with diarrhea. When the bacteria needed to complete food digestion are not present, the undigested food particles sitting in the intestines can create or worsen diarrhea. Adding back the good bacteria can help prevent this digestive malfunction and may improve digestion of dairy products.

Probiotics (often labeled simply "acidophilus") are available in capsule, powder or liquid form; health-food stores typically sell a bottle for $4 to $7. Read instructions as to whether refrigeration is necessary. Or, if lactose intolerance isn't a problem, try yogurt with "live" or "active" cultures of several probiotics. Studies have shown that a container of yogurt a day can help keep yeast infections at bay.