Melee and enemy

I am trying to create a simple survival game step by step i have got to the melee and enemy time i have managed to make a good bit of code which allows the user to press and if the distance is under the max distance it will run a script witch tells the enemy script to run it then reduces the health to 50 then to 0 after i tested this i added a destroy function where when the health is under or equal to 0 it destroys the enemy but when i run the game now the enemy just destroys straight away as if i had hit it twice how do i stop it from doing this here is my code please help

var Health = 100;
function Update ()
{
if(Health <= 0);
{
Dead();
}
}
function ApplyDammage (TheDammage : int)
{
Health -= TheDammage;
}
function Dead()
{
Destroy (gameObject);
}

You are probably applying the damage more than once, in fact many times.

Also, use code tags.

No i have tested it without the destroy game object and it works fine in reducing the health