Contact pustulogens and factors contributing to pustulation were investigated in New-Zealand-white-rabbits. Ammonium-fluoride (12125018), croton-oil (8001283), mercuric-chloride (7487947), nickel-sulfate (7786814), potassium-iodide (7681110), sodium-arsenate (10048950), sodium-lauryl-sulfate (151213) (SLS), or benzalkonium-chloride (8001545) were applied to various sites on the shaved skin of the back at concentrations from 0.01 to 50 percent. Vehicles were white petrolatum, hydrophilic ointment, or distilled water. Vehicle controls were employed. Big Finn chamber, Finn Chamber, and Webril test patches were compared. In some cases, skin was first damaged with a sterile knife, needle, or scarifier. Erythema, papules, vesicles, pustules, induration, necrosis, scaling, and scarring were recorded by visual examination. Clear dose responses were seen with croton-oil, mercuric-chloride, and SLS. Solitary, yellow pustules were obtained from application of 1 percent SLS and 5 percent mercuric-chloride on normal skin. Five percent SLS produced confluent pustules. The few pustules obtained from 40 percent nickel-sulfate and sodiumarsenate had the same appearance, and local erythema was usually slight. Yellow pustules were also produced by 15 percent ammonium-fluoride and these were 2 to 4 millimeters in diameter. Pustules were obtained in all experiments with Big Finn chambers. Petrolatum as vehicle produced pustules more reliably than other vehicles. Pustulation was independent of the site exposed. Of the methods tried, stabbing with a needle gave the most reproducible results. The authors conclude that SLS and mercuric-chloride readily produce pustules in this model. It is suggested that pustulation with these chemicals is an expression of irritancy.