This study was conducted to determineif erythrosine had any effect when placed in contact with alveolar bone and gingival connective tissue in dogs in conjunction with a periodontal surgical procedure. Periodontal surgery was performed on 15 dogs, with a mucoperiosteal flap affording access for introduction of erythrosine (test) or saline (control) solutions, and subsequent flap replacement. The dogs were sacrificed at 2, 7, 10, 14, 21, and 28 days. Autopsy specimens were prepared, stained, sectioned, and examined by light microscopy. The general amount, degree, and type of inflammatory infiltrate was evaluated and recorded. Erythrosine had no apparent effect on the clinical healing time, alveolar bone, or gingival connective tissue in regard to the general degree, type, and location of the inflammation infiltrate based on postsurgical observations.J Periodontol 1991; 62:132–134.