© 2020, Advanced Scientific Research. All rights reserved. Background: The link between immunity and nourishment is clearly known and special attention is being given to its role in the COVID-19 disease. Vitamin B12 is one of the dietary requirements necessary in the treatment of coronavirus patients. Coronavirus patients often show clinical symptoms, such as fever, cough, respiratory distress syndrome, gastrointestinal infection, and fatigue. It is sensible to suppose that COVID-19 affects cobalamin metabolism, impairs intestinal microbial proliferation, and contributes to symptoms of cobalamin deficiency. Such an assumption is based on the fact that there are signs and symptoms of vitamin B12 deficiency that are similar to those of a coronavirus infection. Based on these observations, it can be inferred that treatment with vitamin B12 can be useful in the recovery of COVID-19 patients. Case Report: A 42-year-old healthy female with no chronic illness presented with a 1-week history of pale, weakness and fatigue, cold sensation in the extremities, dizziness and feeling of depression. She was recently diagnosed with mild COVID-19 symptoms but recovered without the need for hospital admission. After recovery, she resumed working but recent symptoms brought her to the doctor’s office. Her laboratory findings revealed low Vitamin B. The attending doctor prescribed intramuscular daily vitamin B ampoules to replace and prevent further deterioration. The doses stopped when acute symptoms reduced, and normal levels were reached. Conclusion: Based on the outcome of the case, recovered COVID-19 patients need to be checked for vitamin B12 deficiency and treated in time to prevent possible deterioration.