Mrs. Dubose was addicted to morphine. She had been addicted to it for many years. Toward the end of her life, she was determined to stop taking it. Atticus said this was because Mrs. Dubose wanted "to leave this world beholden to nothing and nobody" (To Kill a Mockingbird, Chapter 11).

Each day, Jem and Scout went to read to Mrs. Dubose. She was frequently unkind to them, but Atticus insisted that they go. Each day, an alarm clock sounded after Jem had been reading for awhile. After the sound of the alarm, Mrs. Dubose always sent the children home. Each day, the alarm clock seemed to go off at a later time.

After Mrs. Dubose died, Atticus explained to his children about the alarm clock. Mrs. Dubose was trying to break her addiction to morphine. Each time, she tried to go longer and longer without taking it. After the sound of the alarm clock, she sent the children away and took her medication. Atticus explained that while Jem read to their elderly neighbor, "her whole mind and body were concentrated on that alarm clock." In the end, Mrs. Dubose was able to break herself free from the morphine.

The alarm clock symbolized a couple things. It symbolized strength. Mrs. Dubose had to stay strong as she stared at the clock, trying to go longer and longer without morphine. It also symbolized freedom. Each time that the clock went off at a later time, she was one step closer to freedom from her morphine addiction.