Objective: High-dose ascorbic acid leads to the formation of highly reactive oxygen species due to the pro-oxidant effect, resulting in cell death; therefore, used as an additive treatment in several malignancies. We present the results obtained by administration of pharmacological dose of ascorbic acid to conventional chemotherapy in relapsed refractory multiple myeloma patients. Materials-methods: Intravenous ascorbic acid at a pharmacologic dose of 15 gram/week was added to the chemotherapy regimen of relapsed refractory multiple myeloma patients, who received carfilzomib-lenalidomide-dexamethasone treatment and did not respond after the second cycle. Results: The total of 4 patients who had previously received 6–9 lines of myeloma treatment were included. After 4 cycles of chemotherapy + ascorbic acid combination, 1 patient had a complete response whereas other patients had a very good partial response. Conclusion: The addition of pharmacological dose ascorbic acid to conventional chemotherapy can be an effective approach in relapsed refractory patients. Clinical studies with a large number of patients will be useful to evaluate the pharmacological dose of ascorbate in plasma cell disorders.