Probiotics are beneficial bacteria.
Good bacteria help keep the immune system healthy. Your diet and lifestyle largely dictate the balance of good bacteria to bad bacteria hanging out in your body. Things like antibiotics (which kill ALL the bacteria, the good with the bad), long term use of birth control pills, stress, diets high in sugar, wheat, and processed foods all diminish your body's good guy count. Sometimes the bad guys can take over and cause other problems (like yeast and other fungal infections). That's why doctors often recommend eating yogurt when you take antibiotics - because yogurt contains acidophilus and acidophilus is a probiotic.
It is optimal to take a high quality probiotic supplement. You can buy probiotic supplements at any health food store. If you ask where they are, you will most likely be directed to the refrigerated section, as most probiotics need to be in the fridge to stay alive. Here's the deal though: there are several brands of probiotics that are stable at room temp and don't need to be refrigerated. I prefer these. That way, I can simply keep them in my purse and take them at my convenience.
Here are a few brands I like, but there are many:
It's important to have various strains of probiotics in your supplement, too. Some brands have just one strain, some have a bunch. Go for the ones with a bunch and switch them up from time to time, so your body gets lots of different good guys.
In 1964, Dr. R. H. Siver conducted a study using probiotics to treat gastric and intestinal disorders. He discovered that, in addition to improving his patients' gastrointestinal conditions, facial skin cleared up in 80% percent of his patients with acne. And the skin improved within the first two weeks of supplementation. Wow, right? Isn't it crazy that that was in the 60s and to this day most dermatologists still prescribe antibiotics (to teenagers, no less) for acne. The antibiotics only really appear to help while you're taking them, and when you stop, the acne comes back - only now your body is more resistant to antibiotics and probably completely wiped clean of good bacteria.
Here is an article you can read for a little more info.
The skin is the body's largest organ. Your skin looks the best when your body is thriving and healthy. Good bacteria help keep bad bacteria in check which leads to better health. I take them every day. Just sayin'.