The offence of aggravated assault is outlined in section 268(1)(a) of the Criminal Code.
A person commits aggravated assault when they intentionally apply force either directly or indirectly, to another person without that person’s consent and the force wounds, maims, disfigures or endangers the life of the complainant.
Person A and person B get into a verbal argument. Person A strikes person B in the face and head multiple times with a baseball bat. Person B suffers a permanent brain injury as a result.
Person A and person B are in an intimate relationship. During an argument in their driveway, person A hits person B with their vehicle. Person B suffers severe injuries including broken bones and internal bleeding.
R. v. Baylis,  ONCA 41
In R. v Baylis, the offender was charged with one count of aggravated assault and one count of assault with a weapon. While attending a party, the offender attacked another individual, beating the man with his hands, fists, and a baseball bat. The assault caused permanent injuries to the complainant.
R. v. Theriault,  ONCA 517
In R. v. Theriault, the accused, an off-duty police officer, was charged with aggravated assault after becoming involved in an altercation with another individual and hitting the complainant in the eye with a metal pipe. The strike caused the complainant to lose the eye.
Offence Specific Defences
Self Defence or Defence of Another
An individual has the right to use force to protect themselves if necessary. If person B assaults or attempts to assault person A, person A is legally entitled to use force (i.e., commit an assault) against person B in self defence. Person B cannot use any more force than is necessary to stop person A’s assault. An individual may also use the force necessary to defend an attack on another person. This legal defence is outlined in section 34(1) of the Criminal Code.
Defence of Property
An individual has the right to use force to protect their property or to remove someone from their property. The force used must be reasonable and only what is necessary to expel the person from the property. If a person does not have a legal right to the property, they may not use force to remove another person. This legal defence is outlined in section 35(1) of the Criminal Code.
Person A loses balance while walking down a flight of stairs and in an attempt to regain balance, reaches out and knocks over person B, causing person B to fall down the stairs. Person B is severely wounded in the fall. Person A did not intend to make contact Person B, instead their reflex action when falling caused them to make contact with person B.
Assault is not Aggravating
To gain a conviction for aggravated assault, the Crown must prove that the complainant was wounded, maimed, disfigured, or their life was endangered by the actions of the accused. If the injuries sustained by the complainant do not rise to this level, the accused cannot be convicted of aggravated assault.
For example, person A pushed person B causing person B to fall down and cut their knee. The cut is minor and does not require medical attention. This assault does not rise to the level of an aggravated assault. Person A is guilty of assault causing bodily harm or simple assault but not aggravated assault.