The incidence of gingival overgrowth secondary to the administration of cyclosporine A (CsA) is widely reported in renal transplant recipients, while there is no information about periodontal conditions in heart transplant patients. In the present cross-sectional investigation the relationship between clinical periodontal conditions and pharmacological profiles of CsA was determined in 39 patients (31 male and 8 female, aged 18-63 years, mean 45.6 +/- 15.2 years) who possessed their 6 upper and 6 lower anterior teeth. All patients had been on a CsA-based immunosoppression regimen for at least 6 months (6-101, mean 39.3 +/- 30.1). 2 periodontal parameters (recorded on the 12 anterior teeth only) relating to gingival overgrowth were considered: hyperplastic index and % of sites with probing depth > 3 mm. These parameters were always recorded by the same observer at first appointment and 2 months after an oral hygiene programme. Both non parametric statistical analysis (Kruskal-Wallis one-way analysis by rank, Wicoxon signed rank-test and Mann Whitney U-test) and parametric analysis (stepwise multiple regression analysis, one-sample and two-sample t-test) were used to investigate the relationship between the periodontal parameters (dependent variables) and a series of independent variables: age, sex, plaque index (PI), gingival index (GI), CsA dose, CsA blood level, duration of therapy (months since allograft). Results failed to demonstrate any significant correlation between gingival overgrowth and age, sex, CsA dose or CsA blood level, PI. A positive significant correlation was found between periodontal conditions and GI and a significant inverse correlation between periodontal conditions and duration of therapy, suggesting that the relation between CsA therapy and gingival overgrowth in heart-transplant patients could be time-related and the negative influence of the drug on the periodontal status could spontaneously decrease over time.