Hoow do you drop a column in a table

Using phppgadmin, I tried tropping a column in a table. I comes back to
try DROP .. CASCADE. Went into psql and typed the following,

ALTER TABLE "MPC" DROP COLUMNG  do_not_use CASCADE

It appeared to work but did not drop the column. What is the dprocedure
for dropping a column? an anyone point me to a document that tells
EXACTLY how to do this? Also, how do you find out the dependencies it
says it has? I know of none.

Art