Aunt Polly is Tom Sawyer's kind-hearted guardian. She is the sister to the late mother of Tom and Sid.
Aunt Polly wants to raise Tom right, but the high-energy boy is always into some sort of mischief and almost too much of a handful for her. Her chief dilemma is that she likes him too much to want to punish him, and yet she knows it is wrong to let him get away with his hijinks. As she puts it,
Every time I let him off, my conscience does hurt me so, and every time I hit him my old heart most breaks.
Aunt Polly speaks in the dialect of Hannibal, Missouri, and her life is guided by a mixture of religious and folk wisdom. She hits Tom on the head sometimes with her thimble, but mostly, Tom is able to get around her and do what he wants. Sometimes she tries to use her wits or a little well-intended manipulation to get him to behave, but most of the time, this fails. As the narrator says,
Like many other simple hearted souls, it was her pet vanity to believe she was endowed with a talent for dark and mysterious diplomacy.
Aunt Polly is also interested in patent medicines and quack medical therapies. Often the medicines she gives Tom simply make him so drunk that he falls "on the floor expiring with laughter."