Since cytotoxicity-inducing cannabidiol (CBD) shifts the ovarian cancer cell metabolism towards glycolysis, I hypothesized that inhibiting the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) with koningic acid (KA) in the presence of CBD will further enhance their cell death. Ovarian carcinoma cells (SKOV3) were treated with CBD and KA in serum-free DMEM:F12 medium and their viability was assessed with WST-8 reagent. Oxidative phosphorylation status was visualized in the presence of tetramethylrhodamine methyl ester (TMRM), which is an indicator of mitochondrial membrane potential (Δψm). Compared to individual treatments, combination treatment further decreased the cell viability. Cell death was associated with dissipation of Δψm, swelling of the cells and their detachment from the substratum. CBD-induced decrease in pH was reversed by KA. The data support my hypothesis.