NutriBiotic Traveler's Friend is a safe, non-toxic antimicrobial treatment for drinking water. Perfect for camping, boating, fishing and travel to areas where the food and drinking water are questionable. Versatile - can be used to treat one glass of water or several litres at a time. Grapefruit Seed Extract Liquid Concentrate is a natural compound made from the seed and pulp of grapefruit. The grapefruit bioflavonoids (polyphenolics) are converted into a very potent antimicrobial that has been proven to be highly effective in a number of applications.