Ionic Silver(IS)and Colloidal Silver (CS) are both useful. I and my family and friends use IS for external use and CS for internal use. IS is more toxic to viruses and bacteria but are also able to get into your normal cells and with the chemicals in the cells( studies have shown that Ag accumulates in tissues as silver sulfides (Ag2S) and silver selenide (Ag2Se)) So CS is what we use to use internally and my wife (who is a allergic asthmatic) nebulizes with CS and has not had an infection in over 3 years, normally she would require 5 to 6 Antibiotic treatments per year. Not Good! With CS we have not had a cold/flu/infection in over 3 years. You can make both IS and CS at home! Don't let anybod tell you that you can't! It does not take a $500.00 unit to make them! You can make a unit to make both IS/CS for under $100.00 (not counting the silver wire/bar/coin). So keep looking for your info! its out here and not hard to do!!