observations on the epizootiology of "cara inchada" in cattle (ci) indicated that animals affected by the disease recover spontaneously when they are transferred from the ci-prone area to ci-free pastures. in the presente study 13 young bovines with actively progressing periodontal ci-lesions were transferred to a ci-free area, in order to investigate the clinical course of the disease and the composition of the microflora in the periodontal lesions in two distinct situations: (1) in the actively progressing lesions, and (2) in the healed periodontal pouches of clinically recovered animals. the semi-quantitative and qualitative bacteriological study was undertaken in regard to the percentage of black-pigmented bacteroides in cultures. in the actively progressing lesions of the 13 ci-diseased bovines the percentage of these bacteria was 71.3% in average. the evaluation of the composition of the microflora in the healed periodontal pouches of the clinically recovered bovines showed that bacteria of the black-pigmented bacteroides group existed only at an average of 1.7%. the results of this investigation give further support for the infectious nature of the ci-periodontitis and the primary involvement of these bacteria.