Grapevine red blotch-associated virus (GRBaV), which causes grapevine red blotch disease, is an emerging problem for grapevine production in the United States. However, little is known about how viruses, such as GRBaV, affect host physiology even though it is crucial to understanding host-pathogen interactions, symptom development, and potential effects on other pathogens and insect pests including potential vectors. Thus, foliar levels of amino acids, sugars, phenolics and terpenoids were examined in healthy or GRBaV-infected 'Cabernet Franc' (CF) or 'Cabernet Sauvignon' (CS) grapevines both before and after development of red blotch symptoms, in July and September of 2014, respectively. Particular amino acids were increased both before and after symptom development in both cultivars, with some of these amino acids having previously defined associations with host defences. Fructose and glucose were increased in GRBaV-infected CF at both sampling times. However, for CS only, glucose was increased in infected grapevines and only when pre-symptomatic. Phenolic levels were greater in GRBaV-infected CF and CS after symptom expression. Terpenoids were greater in infected CF in July, with no other apparent differences. Taken together, these results demonstrate the effects of GRBaV infection on host physiology, with shifts potentially associated with symptom development and changes in resistance to other organisms.