The effects of prolonged occlusion on the normal microbial skin flora, pH, transepidermal water loss (TEWL) and carbon dioxide emission rate (CDER) were studied. The total average counts before occlusion were 1.8 X 10(2)/cm(2) and increased to 4.5 X 10(6) on day 5. The highest counts were noted on day 4(9.8 X 10(7)/cm(2)). The composition changed: controls comprised of 63% coagulase negative staphylococci, 6% micrococci, 17% diphtheroids and 6% bacilli. After 5 days of occlusion, the percent compositon was: 63% coagulase negative staphylococci, 11% micrococci, 4% diphtheroids, 19% lipophilic diphtheroids and less than 0.003% gram negative rods. The pH of the skin before occlusion was 4.38 and increased to 7.05 on day 5. After 5 days of occlusion TEWL increased from 0.56 mg/cm2/hr to 1.87 mg/cm2/hr and CO2 emmission increased from 25 nl/cm2/min to 118 nl/cm2/min.