[SilentSoul]

Yes , it is

pawn Код:

public OnPlayerTakeDamage(playerid, issuerid, Float: amount, weaponid)
{
    new Float:health;//declaring
    GetPlayerHealth(playerid,health);//checking his health
    if (health < 30.0)//if his health less than 30 you can edit that.
    {
        SetPlayerHealth(playerid, 100);//re-heal him back to full health amount.
    }
    return 1;
}

EDIT: Ops sorry jefff.