Positives

• In a crossover trial, chronic rhinosinusitis patients showed a non-significant trend toward symptom improvement (SNOT-22 mean difference around -13) when switched onto colloidal silver after antibiotics PMC.
  
  
• Post-surgical chronic sinusitis patients tolerated colloidal silver with no major adverse events and no decline in smell-test scores Frontiers.
  
  

Negatives

• A trial participant withdrew because the spray made nasal obstruction and congestion subjectively worse, only resolving once stopped PMC.
  
  
• Patients reported severe nasal burning and stinging with colloidal silver sprays, and four had transient elevations in serum silver levels Frontiers.
  
  

Hurdles & Side Effects

• CRS patients who completed six full weeks of colloidal silver did not meet statistical thresholds for SNOT-22 or Lund-Kennedy improvement, leaving many feeling they wasted the trial period PMC.
  
  
• Long-term or excessive use carries the rare but irreversible risk of argyria (blue-grey skin discoloration), which made some patients hesitant to commit Frontiers.