This is heavily modified version of MobHealth (author Telo) mod which you can find at http://www.curse-gaming.com/mod.php?addid=131

Main function:
display numerical value for currently selected target's hit points.

Features (and how does it differ from MobHealth):
* smaller memory footprint and per sec memory allocation than mobhealth
* works with all language versions
* is almost perfectly accurate - works in groups and when fighting a lot of mobs with same name and lvl
* backwards compatible with mobhealth - all mods that use information from it (for example MobInfo) still work
* uses database that mobhealth already created
* works even with Combat messages disabled
* includes function for easy access to current target's HP from macros and other scripts
* also workes when fighting other players

Instalation:
If you have earlier version of mobhealth installed either delete it, or overwrite it with this one. There is no need to keep both mobhealth1 and mobhealth2. They use same database, so going from mobhealth1 -> mobhealth2 or the other way is safe (you will not lose your old data).
You might want to use /mobhealth2 reset - if your old mob hp data from mobhealth1 is very inaccurate.
After coping to your addons/ folder, there is no other configuration that needs to be done. It JustWorks(tm). After you start to fight any mob you should see it's health displayed on target hp bar.

Note:
At first HP of mob will change a lot, but over time those changes will decrease. After killing around 100 mobs of same type and lvl their max hp will no longer update, even tho it should already almost not change at all after killing 10 or so. You don't have to worry about that - even when fighting your first mob it should be fairly accurate after first attack.

Other sites:
You can also find this addon at two other sites.
Use the one you find most convenient.
http://www.curse-gaming.com/mod.php?addid=1087 (here)
http://ui.worldofwar.net/ui.php?id=681
http://www.wowinterface.com/downloads/fileinfo.php?id=3938

MobHealth2