Thirty patients with lower extremity ulcers of different aetiologies, although mainly of venous origin, were treated with an occlusive hydrocolloid dressing twice a week for a maximum period of 12 weeks. No antibacterial chemotherapy was utilized. A culture was taken of the exudate of the ulcer before commencement of treatment and weekly or bi-weekly thereafter. The results showed a mixed flora with prevalence of Staphylococcus aureus. The average duration of the treatment period was 67 +/- 11 days with a total of 26 patients being healed by the end of this period. The average interval between dressing changes was 4.1 days. Subsequent bacterial cultures showed a persistence of the original flora, but there was no correlation between the type of flora present and clinical evidence of infection or between the type of flora present and the rate of healing of the ulcer. Clinical evaluation of the results obtained with the hydrocolloid dressing was favourable in respect to reduced risk of contamination of the ulcer, lower pain perception and less trauma to the granulation tissue during dressing changes.