As our society ages, neurodegenerative disorders like Parkinson`s disease (PD) 
are increasing in pandemic proportions. While mechanistic understanding of PD is 
advancing, a treatment with well tolerable drugs is still elusive. Here, we show 
that administration of the naturally occurring polyamine spermidine, which 
declines continuously during aging in various species, alleviates a series of 
PD-related degenerative processes in the fruit fly Drosophila melanogaster and 
the nematode Caenorhabditis elegans, two established model systems for PD 
pathology. In the fruit fly, simple feeding with spermidine inhibited loss of 
climbing activity and early organismal death upon heterologous expression of 
human α-synuclein, which is thought to be the principal toxic trigger of PD. In 
this line, administration of spermidine rescued α-synuclein-induced loss of 
dopaminergic neurons, a hallmark of PD, in nematodes. Alleviation of PD-related 
neurodegeneration by spermidine was accompanied by induction of autophagy, 
suggesting that this cytoprotective process may be responsible for the 
beneficial effects of spermidine administration.