Nitrous oxide (N2O), a colorless gas known to have abuse potential, can induce vitamin B12 deficiency that eventually leads to peripheral neuropathy, central nervous demyelination, and myelopathy. N2O abuse has rarely caused subacute combined degeneration of the spinal cord despite being reported in a few studies. Although numerous published studies have demonstrated the toxic effects of N2O abuse, it is still a controversial topic of debate among neurologists. We outline a case of a patient presenting with acute onset of numbness who was ultimately diagnosed with myelopathy secondary to vitamin B12 deficiency induced by nitrous oxide abuse. This case report emphasizes the early diagnosis and management of vitamin B12 deficiency to prevent the severe complications associated with it.