ARDRA of ribosomal genes confirmed that the hyphomycete Scytalidium hyalinum is identical to the coelomycete Nattrassia mangiferae (Hendersonula toruloidea, with arthroconidial synanamorph Scytalidium dimidiatum). S. hyalinum may be just a melanin-less cultural mutant of S. dimidiatum. This explains why the two species are regularly found in the same patient population as agents of human dermatomycosis. Two strains from plant sources were found to be identical to the human strains in ITS-RFLP patterns. RFLP of SSU and LSU was hampered by the frequent occurrence of introns. Profiles of secondary metabolites were studied using TLC, GC and GC/MS. Production of metabolites varies considerably with the strain, but two naphthoquinone compounds were nearly always present. Selected-ion monitoring (SIM) of these compounds enabled the specific recognition of the taxon.