Symphytum officinale is a perennial plants native to Europe and Asia. 
This plant has a long history of cultivation as a medicinal plant. 
In the middle ages, it was a famous remedy wounds, scratches and other skin irritations. 
Nowadays, the whole plant is used in Western herbal medicine for external wound healing and pain. 
Research shows that its allantoin, 5-ureide-hydantoin, possesses a wound healing effect in clinical trials. 
The healing mechanism occurs via the regulation of inflammatory reactions showing increased proliferation of fibroblasts. 
Comfrey leaf extracts have shown to effectively induce healing activity which was confirmed by an increase in collagen deposition 
and a reduction in cellular inflammatory infiltrate, while another study demonstrated anti-irritant activity at a cellular level.