Paradoxical growth was noted in RPMI 1640 and antibiotic medium 3 in the case of 14 and 1 of 15 Candida tropicalis strains, respectively, at a caspofungin concentration of 12.5 microg/ml using minimum fungicidal concentration tests. Time-kill assays showed that against isolates killed at lower concentrations, caspofungin at a concentration of 12.5 microg/ml was only fungistatic.