Migraine, or severe headache, is caused by narrowing of the arteries of the brain or congenital vascular disorders in its areas. Leech saliva has relaxing, vasodiating effect which eases the spasms or completely removes them. Hirudin in leech saliva thins the blood which eases the blood flow.Enzymes such as apyrase, destabilase and others help to clean the blood vessels from plaques, clots and unhealthy atherosclerotic deposits.
Kininase in leech saliva act as a painkiller.All of these actions combined can considerably improve the circulation and improve the blood flow.