This formula is considered to be a very effective natural antibiotic and a natural antihistamine. The individual ingredients including oil of oregano have been known for these purposes for many years. NutraPerfect combined them for total effectiveness. It can be taken as needed at the beginning of a cold or during allergy season. If caught early enough; a cold may not even develop into a full siege lasting weeks. Many have reported efficacy within 24-48 hours.