Epistaxis from the anterior septum is frequently treated with a topical application of silver nitrate. There are two concentrations commercially available and in use by otolaryngologists, these are 75% and 95% silver nitrate. The purpose of the present study was to investigate the histological effect of the two different silver nitrate concentrations on mucosal tissue at a fixed contact time of 5 s. Twelve children undergoing routine tonsillectomy were included in this study. Prominent blood vessels on the mucosal surface of the tonsils were identified and a single vessel on each tonsil was selected for application of either 75% or 95% concentration of silver nitrate for 5 s. Depth of penetration across the tonsil tissue was measured following application of the two different silver nitrate concentrations. This study demonstrated a significant difference in depth of tissue penetration with the 95% averaging a twofold increase in penetration depth. It is likely that the increased depth of penetration with 95% silver nitrate may increase the risk of complication of nasal cautery such as septal perforation, particularly in patients undergoing repeated or bilateral nasal cautery.