What are some arguments I can use to support euthanasia?

If asked to support euthanasia (I assume you mean
voluntary euthanasia or assisted suicide, not a situation where some other person
decides who lives and dies), I would make the following
arguments:

• Personal freedom.  A person should
  have the right to control their own life.  This should include the right to decide when
  (perhaps within some limits) they would like to
  die.


• Prevention of unnecessary suffering.  People who are
  suffering from terminal illnesses often have to deal with terrible pain for the last
  months of their lives.  People who are in the early stages of Alzheimer's have to deal
  with the idea that they will become a total burden to their families without even being
  able to recognize or love those families.  Both of these are terrible things and people
  should be able to avoid them.


• Economic reasons.  Imagine
  if you had to choose between dying at a given time or living (at huge expense) for a few
  more months.  Shouldn't you have the choice to leave your money for something (like your
  grandkids' college education) that means more to you than a few more months of
  life?

All of these are possible arguments for
euthanasia.