Four strains each of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) were found to differ in their response to 2-deoxy-D-glucose. In the presence of 0.1% deoxyglucose, all 4 strains of HSV-1 synthesized a new major glycopeptide (C5’) with an apparent molecular weight significantly less than the corresponding major glycopeptide (C5) synthesized in the absence of the compound. On the other hand, with all 4 strains of HSV-2 the synthesis of the major C5 glycopeptide in the presence of deoxyglucose remained essentially unaltered. The compound inhibited the replication of both types of viruses in an identical fashion, yielding at a concentration of 0.1%, 99% or greater reduction in infectivit