API:UnitMaxHealth

Get the maximum health of a unit.
UnitMaxHealth("unit")
== Parameter ==
:;unit
::String - the UnitId (e.g. "target", "party1", "raid1", etc..) 
== Returns ==
:;health 
::Integer - maximum health of the specified unit. Returns 0 if the specified unit does not exist (eg. "target" given but there is no target).
== Example ==
Print your maximum health to the Say channel.
SendChatMessage("My health is " .. UnitMaxHealth("player"),"SAY")
UnitMaxHealth