Quorum sensing (QS), or the control of gene expression in response to cell density, is used by both gram-negative and gram-positive bacteria to regulate a variety of physiological functions. Increasing evidence implies that certain eukaryotes produce QS-inhibitory compounds. In this work, we tested Tremella fuciformis for their ability to inhibit QS-regulated behaviors. T. fuciformis fruiting bodies were dried and extracted using 75% (v/v) aqueous methanol. The crude extract was redissolved in appropriate concentrations of dimethyl sulfoxide (DMSO), sterilized by filtration through a 0.45-mu m membrane filter and added to Chromobacterium violaceum CV026 cultures, which was used to monitor QS inhibition. Inhibitory activity was measured by quantifying violacein production using a microplate reader. The results have revealed that the DMSO-soluble compounds extracted from T. fuciformis could inhibit violacein production, a QS-regulated behavior in C. violaceum. The results suggest an attractive tool to control and handle detrimental infections caused by human, animal, and plant pathogens. Further studies are required to isolate specific substances from T. fuciformis extract acting as QS inhibitors.