Silver sulfadiazine acts only on the cell membrane and cell wall to produce its bactericidal effect.

Studies utilizing radioactive micronized silver sulfadiazine, electron microscopy, and biochemical techniques have revealed that the mechanism of action of silver sulfadiazine on bacteria differs from silver nitrate and sodium sulfadiazine. Sufficient data have been obtained to demonstrate that silver sulfadiazine will inhibit bacteria that are resistant to other antimicrobial agents and that the compound is superior to sulfadiazine. Results from in vitro testing are listed below. It is bactericidal for many gram-negative and gram-positive bacteria as well as being effective against yeast. Silver sulfadiazine has broad antimicrobial activity.