The accused, a woman in her 40s, was sentenced on Tuesday by a court in Nyon, in the canton of Vaud, reported newspaper Le Tribune de Genève.
The court found that the biology graduate wanted to get rid of the wife of a businessman she had been romantically involved with before he married.
The man was also her employer and paid the rent on her accommodation.
Taking advantage of the fact that her intended victim was an alcoholic, the accused placed several bottles of whisky in some bushes near the woman's home and let her know anonymously that it was there, reported Le Tribune de Genève.
The victim took the bait and drank a whole bottle during the course of one day.
On later analysis of another of the bottles by cantonal authorities, it was found to contain a mixture of whisky and hydrochloric acid.
According to a medical report the victim suffered from vomiting and abdominal pain.
A single bottle was not enough to kill her, the report said, but the accused intended her plan to work slowly but surely.
“The defendant made the choice to eliminate her rival by killing her little by little without concerning herself with the suffering she would inflict,” said the judges.
“With her above average knowledge [of the subject], she couldn't not know the effects of the poison.”
The victim poured a second bottle of the whisky down the drain after realizing it had been opened.
Her son then discovered the plan and was able to stop it going any further.
The court convicted the defendant of attempted murder and sentenced her to five years in prison.
She had previously been held in prison from January to May 2013 whilst awaiting trial, before the victim's husband paid her 10,000 franc bail, said the paper.