The optimum teicoplanin loading dose and duration of therapy required for rapid attainment of a therapeutic trough plasma concentration (C(min)) (> or = 10mg/L for serious Gram-positive infections and > or = 20mg/L for deep-seated infections) are not known. In this open-label, multicentre, observational study, teicoplanin levels were determined following administration of loading doses of 6 mg/kg every 12h on Day 1 followed by 6 mg/kg once or twice daily to hospitalised patients with suspected or diagnosed Gram-positive infections. C(min) levels for the first 4 days of treatment were collected 15min prior to drug administration. Levels were determined with an Abbott TDx/FLx Analyzer and Seradyn Teicoplanin Innofluor Assay Kit. The two target trough values (> or = 10mg/L and > or = 20mg/L) were only achieved by Day 4 in the once-daily group (n=34; mean 9.55 mg/L, 95% confidence interval (CI) 8.17-10.94 mg/L) and in the twice-daily group (n=40; mean 21.8 mg/L, 95% CI 17.21-26.39 mg/L), respectively. However, the mean C(min) in the twice-daily group was > or = 10mg/L (11.03 mg/L) by Day 2. To achieve rapid therapeutic C(min) concentrations targeted for the majority of serious Gram-positive infections, we recommend teicoplanin loading doses of 6 mg/kg every 12h for 48h followed by once-daily for infections other than infective endocarditis, septic arthritis and osteomyelitis. Regarding the latter infections, higher loading doses might be warranted to reach rapid steady-state concentrations.