Ceramide trihexoside (CTH) is a glycosphingolipid found mostly in mammalian cell membranes. It is involved in cellular signaling and has been identified as a receptor for various toxins including shiga toxins and shiga-like toxins.1 Some toxins, such as veratoxins from Escherichia coli, require specific fatty acids on the ceramide portion of CTH to show affinity in binding. An accumulation of CTH in the cellular membranes due to a lack of alpha-galactosidase to convert it into lactosyl ceramide results in Fabry disease.2 This product can be used as an excellent standard for the identification of CTH in Fabry disease by HPLC3 and mass spectrometry.4 An inability to convert CTH to globoside due to mutations in the gene sequence leads to the Pk blood group phenotype. It appears that under certain conditions CTH can enhance anticoagulant activity. CTH has also been studied as a tool to investigate lymphocyte activation.5 Neutral glycolipids may help to cause resistance to natural killer cells in some types of cells. Interferon appears to slightly increase the resistance of cells towards natural killer cells and also increases the amounts of non-hydroxylated fatty acids on various glycolipids, suggesting that there may be a connection between the hydroxylated fatty acids and natural killer cell resistance.