Natural Factors is a leader in probiotic science and innovation with over 35 years' experience. Ultimate Probiotic Critical Care is a proprietary blend of 9 gastric-resistant strains with a powerful concentration of 100 billion active cells (at time of expiration) that work synergistically for maximum activity and efficacy.* It supports a positive balance of microflora, helps maintain a healthy immune system and digestive strength. It also promotes healthy intestinal flora and helps to create a favorable environment for absorption of nutrients.* Enteric coating is not required for all probiotic strains. With regard to stomach acid resistance, not all strains are created equal. Natural Factors has carefully selected naturally acid-resistant strains so that they may be consumed at any time, with or without meals, and are safely delivered to the intestine unharmed. Our strains are tested for their viability in the stomach to ensure optimal absorption and efficacy.