Practical Magics hidden message is that men always leave women early, but women's need to be loved by men keeps them going on searching for that love. This is the story author's view of life. But it is also a celebration of women and womanhood and a rebellion against people who stereotype all witches as being evil.
The movie's family has had a history of witchcraft that has passed on from every woman in the family on to the girls of the family, Bullock, Kidman and their daughters. The women in the family never give birth to boys, and therefore, since there are no men in their families, except for the men they meet and marry, there are no men who carry these powers and romantic tragedy.
Most of the women in their town are apprehensive of their lifestyle and view them as evil and as a connection to the Devil.
As the movie progresses, Kidman's boyfriend turns abusive and evil and dies during a drunken binge. He is revived by Kidman and comes back as a monster and starts attacking everybody. Kidman is spritually overtaken and Bullock hears her in her mind and goes to rescue her. Bullock's daughter's find Kidman. Bullock and Kidman assist in the destruction of Kidman's boyfriend.
As this is all going on, Bullock, on the other hand, loses her husband and the love of her life, but she understands that no matter what she does, nothing can really bring back her old love, so she has the task of raising her own daughters by herself.