Abstract Adult rat neurones of the dorsal motor nucleus of the vagus (DMNV) react more severely to axon injury than most other peripherally projecting neurones. Following axon injury, DMNV neurones atrophy and die such that after 18 months only 25% remain. In contrast, the majority of somatic motor neurones (e.g. in the hypoglossal nerve) survive axon injury. The reasons for this difference are unknown. We administered a brief pulse of fibroblast growth factor-1 (FGF-1 or acidic FGF) to the vagus nerve trunk immediately after applying a standardized crush injury to the nerve. FGF-1 increased the number of axons regenerating in the injured vagal nerve and the number of neurones surviving in the DMNV 9 weeks after injury. This is to our knowledge the first demonstration of a peptide growth factor that ameliorates this distinct degeneration of DMNV neurones in vivo.