Just drink water from fountain & you'll get full life

if you mean that their is no limitations of life i.e. the bar which shows life meter is
fully filled then their are certain places where you get life upgrades . whenever you see
an semicircular fountain drink water from it and you magically enter a new place filled
with death draps if u succsesfully p*** through the traps you will see a bright light
,just walk towards it . then u will magically come near the fountain and you will see
prince laying down and he stands up as if he eas watching a dream . and yeah the fountain
will automatically break after you p*** through the traps . oh your max health will also
increase .there are total 6 life upgrades in the game if u get all of them then in the end
of the game u will fight the dark prince also after u defeat vizier . also if u do not get
through the traps and die then u will wake up near the fountain and your health NOT MAX
HEALTH will decrease but the fountain will still be there so u can try again .

if u want full health then just search for the semi circular fountains (there r six of
them in holl game) search them and continue ur gameplay after drinking water from the
fountain and u just have to complete a little task.