On March 11, 2013 Bill C-26, Citizen’s Arrest and Self-defence Act came into force. Prior to that date, the Code provisions on self-defence stated as follows:
The difference between s. 34(2) and 35 are that s. 35 are restricted to cases where the accused is the initial aggressor by provocation or assault. Section 35 also does not explicitly restrict the use of force in cases of "unlawful assault" and s. 35 requires that the accused must have "declined further conflict and quitted or retreated from it as far as it was feasable to do so".
Proof of Defence
For all the offences the burden is on the Crown to prove beyond a reasonable doubt the defence does not apply
Unprovoked assault: s.34(1)
- accused made no provocations
- assault by the victim on the defendant
- no intention by the defendant to cause death or grievous bodily harm at time of assault
- no more force than is necessary to self-defence
- R v Cinous, 2002 SCC 29 (CanLII),  2 SCR 3, per McLachlin CJ and Bastarache J, at para 39
see R v CJO, 2005 CanLII 43518 (ONSC), per Tulloch J, at para 21
R v Grandin, 2001 BCCA 340 (CanLII), 154 CCC (3d) 408, per Finch JA (3:0), at para 35
R v Bailey, 2010 BCCA 167 (CanLII), 253 CCC (3d) 509, per Saunders JA (3:0), at para 26
Assault Causing: s.34(2)
The crown has the burden of disproving
- the accused was
- actually assaulted, or
- the accused
- subjectively apprehended he was being assaulted;
- it was reasonable to believe he was being assaulted; and
- the assault was reasonably apprehended would be unlawful.
- the accused caused death or grievous bodily harm;
- the caused result was done in repelling an assault;
- the accused was under a reasonable apprehension of death or grievous bodily harm by the initial assailant;
- the accused believed on, reasonable grounds, that he could not otherwise preserve himself from death or grievous bodily harm.
- the accused apprehended imminent danger
R v Pétel, 1994 CanLII 133 (SCC),  1 SCR 3, per Lamer CJ ("(1) the existence of an unlawful assault; (2) a reasonable apprehension of a risk of death or grievous bodily harm; and (3) a reasonable belief that it is not possible to preserve oneself from harm except by killing the adversary.")
see also R v Mohamed, 2014 ONCA 442 (CanLII), 310 CCC (3d) 123, per Rouleau JA (3:0), at para 16
Provoked assault: s.35
- the accused assaulted a person
- the accused did not assault intending to cause death or grievous bodily harm or has not provoked the assault
- the accused used force where:
- he was under a reasonable apprehension of death or grievous bodily harm from the person assaulted and
- the accused had a reasonable belief that the assault was necessary to preserve himself from death or grievous bodily harm.
- the accused, at any time before the necessity of preserving himself, did not endeavour to cause death or grievous bodily harm;
- the accused avoided conflict as far as it was feasible before the necessity arose.
Preventing assault: s.37
The crown has the burden of disproving at least one of the elements of the defence beyond a reasonable doubt:
- force was for the purpose of preventing an assault on self or person under his protection.
- no more force than necessary to prevent assault or repetition having regard to the nature of assault to be prevented
- the force was proportionate to the danger threatened.
R v McIntosh, 1995 CanLII 124 (SCC), 95 CCC (3d) 481, per Lamer CJ
R v Grandin, 2001 BCCA 340 (CanLII), 154 CCC (3d) 408, per Finch JA (3:0), at para 36
R v Shannon, 1981 CanLII 332 (BC CA), 59 CCC (2d) 229, per MacDonald JA
R v Thomas, 2002 BCCA 612 (CanLII), 170 CCC (3d) 81, per Rowles JA (3:0)
- R v McIntosh, 1995 CanLII 124 (SCC), 95 CCC (3d) 481, per Lamer CJ at 44
- McIntosh, ibid. at 44
Unprovoked: s. 34(1)
Section s.34(1) of the Criminal Code justifies the use of repelling force by force if the force he used was not intended to cause death or grievous bodily harm and was no more than was necessary to enable him to defend himself. The onus is on the Crown to prove beyond a reasonable doubt that self-defence under s.34 is not available to the accused. 
Any provocation eliminates the use of this defence.
The fact that the accused does not retreat from a confrontation does not preclude him from relying on s.34. Likewise, an accused does not need to be reduced to a state of frenzy  and the accused does not need to rely upon detached reflection of his options where circumstances do not allow.
It is not necessary that an assault actually occur. The accused must simply have a reasonable belief that he is about to be unlawfully assaulted.
R v Latour, 1950 CanLII 12,  SCR 19, per Fauteux J
R v Nadeau, 1984 CanLII 28 (SCC),  2 SCR 570, per Lamer J
R v Westhaver, 1992 CanLII 2545 (NSCA),  NSJ 511 (NSCA), per Freeman JA
- R v Nelson, 1992 CanLII 2782 (ON CA), 71 CCC (3d) 449, per Morden ACJ (‟Self defence is not available where the accused provokes the attack”)
R v Deegan, 1979 ABCA 198 (CanLII), 17 AR 187, per Harradence JA
R v Westhaver, 1992 CanLII 2545 (NSCA), 119 NSR (2d) 171, per Freeman JA (3:0) , at para 8
- R v Antley, 1963 CanLII 258 (ON CA), 2 CCC 142, per Roach JA (2:1)
- R v Kandola, 1993 CanLII 774 (BC C.A.), 80 CCC (3d) 481, per Wood JA (3:0)
- R v Kong, 2005 ABCA 255 (CanLII), 200 CCC (3d) 19, per Fraser JA (2:1), at para 186 aff’d 2006 SCC 40 (CanLII), per Bastarache J
No Intention to Cause Bodily Harm
Where the evidence raises the issue of whether the accused intended to cause bodily harm 'the judge must instruct the jury on both s. 34(1) and (2)
When Causing: s.34(2)
Section 34(2) is available regardless of whether the assault was provoked.
The defence is available even where there was an intention to cause GBH or death.
There is no requirement that the force be no more than is necessary to defend against the assault.
Though not explicitly stated in the s. 34(2)(a), a further requirement that the accused have apprehend imminent danger at the time of the assault has been read into the defence.
All elements of this defence require that the jury determine the perceptions of the accused at the time and whether those perceptions were reasonable.
- R v McIntosh, 1995 CanLII 124 (SCC),  1 SCR 686, per Lamer CJ (5:4), at para 42
- R v Tromblley, 1998 CanLII 7128 (ON CA), 126 CCC (3d) 495, per Carthy JA (2:1) aff'd 1999 CanLII 681 (SCC),  1 SCR 757, per Lamer CJ
R v Siu, 1992 CanLII 1014 (BCCA), 71 CCC (3d) 197 at 209 (BCCA), per curiam (3:0)
R v Pintar, 1996 CanLII 712 (ON CA), 110 CCC (3d) 402, per Moldaver JA (3:0)
see R v Reilly, 1984 CanLII 83 (SCC), 15 CCC (3d) 1, per Ritchie J (6:0)
R v Baxter, 1975 CanLII 1510 (ON CA), 33 CRNS 22, 27 CCC (2d) 96, per Martin JA
R v Bogue, 1976 CanLII 871 (ON CA), 13 OR (2d) 272, 30 CCC (2d) 403, 70 DLR (3d) 603, per Howland CJ
- Petel, supra
A person is not required to retreat from his home.
An accused defending himself against a reasonably apprehended attack expected to weigh his response "to a nicety" when dealing with an unprovoked assault under section 34 (1) or (2).  in a jury trial instructions on this issue are known as "Baxter instructions".
Failure to give Baxter instructions is an error of law.
Section 35 requires the use of force (a) under reasonable apprehension of death or grievous bodily harm from the violence of the person whom he has assaulted or provoked, and (b) in the belief, on reasonable grounds, that it is necessary in order to preserve himself from death or grievous bodily harm and (c)must have “declined further conflict and quitted or retreated from it as far as it was feasible to do so before the necessity of preserving himself from death or grievous bodily harm arose.” 
Section 35 does not require the accused to be responding to an "unlawful" assault.
Everyone may use force to defend themselves or someone in their protection.
This right does not extend to retaliation where the accused's self-preservation is not in peril.
- R v Brisson, 1982 CanLII 196 (SCC),  2 SCR 227
Grievous Bodily Harm
Grievous Bodily Harm (GBH) is "either permanent or dangerous; if it be such as seriously to interfere with comfort or health it is sufficient"
GBH can include sexual assault.
- R v Martineau, 1988 ABCA 274 (CanLII),  AJ No 716, per Laycraft JA upheld in 1990 CanLII 80 (SCC),  2 SCR 633, per Lamer CJ, at paras 52, 53 citing R v Bottrell, 1981 CanLII 352 (BC CA), 62 CCC (2d) 45, per Anderson JA (2:1) and others
- R v XJ, 2012 ABCA 69 (CanLII), 524 AR 123, per curiam (3:0), at para 11
Proportionality: "No more than reasonably necessary"
The words "no more force than is necessary" can be equated with the requirement of the force being "reasonable in all the circumstances"  Force that is "clearly disproportionate to what was required under the circumstances" must fail.
Proportionality has two aspects. The force must be considered reasonable in all the circumstances including the accused's subjective belief as to the nature of the harm or danger, but the objective component of the defence is also required.
Seriousness of an injury does not necessarily mean that the force used was excessive.
Proportionality must be considered in light the "heat of the moment" where the accused is "filled with a combination of adrenalin and fear" such that he is not expected to always react both quickly and "measured to perfection to the nature of the risk of danger posed."
- R v Gunning, 2005 SCC 27 (CanLII),  1 SCR 627, per Charron J (9:0), at para 25
- R v McKay, 2009 MBCA 53 (CanLII), per Chartier JA (3:0) - in relation to 41(1)
R v Szcerbaniwicz, 2010 SCC 15 (CanLII),  1 SCR 455, per Abella J (5:2), at paras 20 and 21
R v Philpott, 2011 NLTD 6 (CanLII), per LeBlanc J at 42
R v Baxter, 1975 CanLII 1510 (ON CA),  27 CCC (2d) 96, per Martin JA, at p. 111
- R v Marky, 1976 ALTASCAD 125 (CanLII), 6 WWR 390, per McGillivray JA
R v Heydari, 2014 ONSC 2350 (CanLII), per Campbell J, at para 6
See also R v Antley, 1963 CanLII 258 (ON CA), 1 OR 545 (CA), per Roach JA (2:1), at pp. 549-550
Baxter, supra, at p. 111
R v Hebert, 1996 CanLII 202 (SCC),  2 SCR 272, per Cory J (5:0), at p. 281