Kuntal Patel had denied trying to kill her mother, Meena Patel, by spiking her Diet Coke with deadly abrin after she forbade her to marry her boyfriend, Niraj Kakad.
The jury at Southwark Crown Court found Patel guilty of acquiring a biological agent or toxin but cleared her of attempted murder.
The jury of six men and six women deliberated for just over three hours to arrive at the verdict at the end of a two-week trial.
The plot had been described at her trial at Southwark Crown Court here as being inspired by hit US TV series 'Breaking Bad'.
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Taking to the witness box earlier this week, Kuntal dabbed tears away from her eyes with a handkerchief as she spoke about how her mother beat her and called her a "fucked-up-brain girl".
Kuntal lived with her mother and younger sister, Poonam, in east London, where her mother kept tabs on her round the clock and "started slapping" her "on and off".
She turned to an Asian matrimonial website to find a man she could marry and have children with - but her "manipulative" mother even wrote her online dating profile for her. When she struck up a relationship with Kakad, her mother quickly turned sour and tried to break them up, the jury was told.
Kuntal said she respected her mother's views. "I knew she was just frightened and we didn't have much family support and I knew that as a mother she was worried about me," she said.
Kuntal denied trying to murder her mother, who sits on the bench at Thames magistrates court, and acquiring a biological agent or toxin. She has pleaded guilty to two counts of attempting to acquire a biological agent or toxin last December.