What are probiotics, and just why are they so important to your health? Probiotics are often referred to as the good bacteria or gut bacteria, and most people equate this to eating yogurt and yogurt by-products. These good bacteria go by names like lactobacillus. Probiotics supplement the balance of healthy bacteria in your gut. It's essential to take in an adequate amount of these good bacteria each day. They help improve your digestive ability, bolster your immune system, and help with your overall mental health.