Need help with my health script

My health script keeps sending the error ‘Unexpected token “(”’, can anyone help?
Here it is:

function (OnCollisionStay(collision:Collision)){
    if (collision.collider.tag == "enemy");{
 	curHealth = curHealth-10;
};

Check out the proper syntax: Unity - Scripting API: MonoBehaviour.OnCollisionStay(Collision)

OnCollisionStay should not be in brackets, also semicolon after if() is unnecessary, and you missed a bracket after subtracting health.

function OnCollisionStay(collision:Collision){
    if (collision.collider.tag == "enemy"){
        curHealth -= 10; //Same as curHealth = curHealth - 10;
    }
};