Health UI, how to make player loose health

I have a script here for a player health system, i am struggling to figure out how to make it that if the player is touched by “enemy” they loose one health.
Thanks

using UnityEngine;
using System.Collections;

public class HealthSystem : MonoBehaviour
{
public int maxHealth = 3;
public int currHealth = 3;

public float healthBarLength; 

void Start ()
{
	healthBarLength = Screen.width / 2;	
}

void Update ()
{
	AddjustCurrentHealth(0); 		
}

void OnGUI() 
{
	GUI.Box(new Rect(10, 10, healthBarLength, 20), currHealth + "/" + maxHealth); 
}		

public void AddjustCurrentHealth(int adj) 
{
	currHealth += adj;
	
	if(currHealth > maxHealth)
		currHealth = maxHealth;
	
	
	if(currHealth < 0)
		currHealth = 0;
	
	
	if(maxHealth < 1)
		maxHealth = 1;
	
	
	
	healthBarLength = (Screen.width / 2) * (currHealth / (float)maxHealth);
}

}

You could use the OnCollisionEnter function. Here is a discussion of someone trying to do something similar. In the function definition, I suggest you check the tag of the colliding gameObject and only subtract health if where applicable (i.e. player vs enemy, but not player vs wall).

If you attach the script to the player object, you could also increase the player’s health when they walk over a health pack, as another example of this function’s usage.

Hope this helps!

Cheers

Bilo

Couldn’t get much from that.

I tried this but nothing happened when they collided

void OnTriggerEnter(Collider other)
{
if (other.gameObject.tag == “EnemyBall”)
{
currHealth = currHealth - 1;

	}	

}