Topical
Iodine has bactericidal activity, e.g. a 1% tincture will kill 90% of bacteria in 90 seconds, a 5% tincture in 60 seconds and a 7% tincture in 15 seconds
Oral
The primary function of iodine is to control the rate of cellular oxidation through its presence in the biosynthesis of iodated thyroid hormone.