Oral contraceptives didn't start with The Pill. Ancient recipes for preventing pregnancy contained all kinds of natural ingredients for desperate people. Their effectiveness varied, and none are recommended.
Modern testing has revealed that other herbs and plants recommended by ancient authors, such as cow parsnip and the wild yam called Barbasco root, contain chemicals that can influence hormone levels. Of course, not all oral contraceptives had to contain plant matter: Native women in today’s New Brunswick brewed tea out of preserved beaver testicles, which could have provided androgen to influence their hormonal balance and decrease fertility.
Read about other historical birth-control schemes at Discoblog. Link
(Image credit: Flickr user faster panda kill kill, altered at Speechable)