Clara Bandick, who played Auntie Em in The Wizard Of Oz, offed herself the same way. From imdb.com:
"On Palm Sunday, April 15, 1962, Clara went to church in Hollywood, California. When she returned she wrote a note stating she was about to take the greatest adventure of her life. She took an overdose of sleeping tablets and pulled a plastic bag over her head, thus ending her life. She was 81 years old."
I remember reading Blandick was going blind and was suffering from arthritis.. poor thing didn't want to suffer anymore