The present study investigates the de- and regenerative changes in the saphenous nerve of the rabbit following systemic treatment with a combination of the vitamins B1, B6 and B12 and a control group that was treated with physiological saline solution. Cold lesion of the nerve, which led to an optimal axonotmesis, was used to cause a secondary degeneration. After 4, 10 and 21 days the nerves were removed and investigated by light and electron microscopy. The morphological results show that the number of regenerating axons is higher and that of degenerating axons lower in the group treated with the given doses of the vitamins than in the comparable control group. Statements as to the metabolic processes and vitamins from which the better regeneration results are due are as yet not possible. Further investigations with the individual vitamins are necessary. Clinical indications of neurotoxicity due to the dose levels used were not observed in any of the cases.