This product inhibits the growth of cells, including cancer cells. D-threo-PDMP has been shown to inhibit cell growth by inhibiting the enzyme glucosylceramide synthase1 but erythro-PDMP inhibits growth according to a different mechanism. PDMP has four possible isomers (D-threo, L-threo, D-erythro, and L-erythro) due to its two chiral centers. This product (D,L-erythro-PDMP) is a mixture of D-erythro (1R,2R) and L-erythro (1S,2S). The D-threo isomer has been shown to be the active glucosyl ceramide synthetase inhibitor.2 Although erythro-PDMP does not inhibit glucosylceramide synthase it does cause cell growth inhibition similar to threo-PDMP.3 This has been suggested as a treatment for cancer.4 In addition to its stereochemistry, the acyl chain of PDMP has a very marked effect on the intensity of the inhibitory action of the molecule.