A woman was given the maximum fine of $2,500 on Tuesday for spraying insecticide at a neighbour's one-year-old son.
Kong Yong Meow, 59, pleaded guilty to committing the rash act and endangering the personal safety of others, reported The Straits Times.
The incident took place on June 25, 2011 along the common corridor outside Kong's flat in Bedok North Avenue 1.
The English daily reported that Kong, who works as an IT programmer, became unhappy after the one-year-old victim and his brother started making noises while playing outside of her unit.
She had shouted at the victim before spraying insecticide at him.
The boy's mother carried him away upon seeing this, and The Straits Times reported that the child rubbed his eyes due to discomfort, and also vomitted twice after the incident.
The boy's father called the police.
In mitigation, Kong's lawyer Tng Kim Choon said she had never been in trouble with the law before. He also said she was very stressed and had even contemplated suicide a few times due to the strained relationship with her neighbours.
She thought that spraying insecticide outside her flat would discourage the children from sitting on the steps, but added that she did not intend to hurt anyone.
Psychiatrists found that Kong had been suffering from insomnia and a mood disorder for at least two years.
In addition to the fine, Kong could also have been jailed up to six months.