Twenty people have died in one-punch attacks - often fuelled by alcohol - in Northern Ireland since 2004, police have said.
The PSNI said the fatal assaults had destroyed the lives of the victims and their families as the force re-launched a Facebook campaign to raise awareness.
Detective Chief Inspector Karen Baxter said: "With just one punch, lives have been destroyed and families' lives have been wrecked.
"The majority of these incidents are fuelled by alcohol and can have a devastating impact on the victim and their family.
"The offender will likely face a murder or manslaughter charge and have a criminal record for the rest of their life.
"This type of conviction also imposes restrictions on their ability to travel."
The campaign is aimed at 18 to 25-year-old men and highlights the risks of getting involved in an argument or fight which could lead to serious injury or death.
DCI Baxter added: "Raising awareness of One Punch is timely as most students and young people are now off for summer break. It is a busy time socially for people - our message is to enjoy their night out, but more importantly - to stay safe."