replacing literal " in string

Could somebody help me with the correct syntax for an ereg_replace to replace literal occurences of the quote character in a string. I can't seem to get it right. In other words, I have a form input variable -- that literally may look like this: "some_value", and I want it to literally look like this: some_value. I tried: $key=str_replace ("\"", "", "$key"); and other variations but can't get it to work. What am I missing? Thanks!