The Gram-positive bacteria Kocuria rhizophila DC2201 were selected from the screening test in order to identify the strains that failed to cause cytolytic by various organic compounds. K. rhizophila have been shown to be much more susceptible to long-chain alcohols than short-chain alcohols as well as other Gram-positive bacteria and Gram-negative Escherichia coli. However, we found the unique cell structural properties of K. rhizophila for aliphatic alcohol exposure. K. rhizophila exposed to alcohols showed no changes significantly in both cytomorphology and cytoplasmic membrane fluidity even when lethal concentrations were used. Meanwhile, alcohols dramatically altered the individual cell size, intracellular structures, and cytoplasmic membrane fluidity of E coli. These results provide evidence that K. rhizophila has potentially robust cell structures against organic compounds. (c) 2006 Elsevier Inc. All rights reserved.