
Almost all young children at one time or another resort to aggressive behaviour for various reasons. When toddlers get hostile, adult intervention is essential, but it's important to understand that many hostile acts are basically a reflex at this stage of development.
Even kids who often demonstrate that they know better sometimes resort to aggressive acts to get what they want. Those kids who have a somewhat belligerent "short-fuse" personality require even more supervision as they learn to control their impulses.
Stop the unacceptable behaviour immediately, but gently; hold hands with the child and encourage him to take a deep breath with you.
Try to surmise what happened yourself by a quick observation; angry interrogations often get conflicting replies or no answer at all.
Bend down so you can look straight into their eyes; often no words are necessary.
Acknowledge the bad feelings that provoked the aggression, followed by clearly stating that the rule that was rule.
The less you talk, the more likely the child is to hear what you say.
Restore the peace by redirecting both kids to a parent-supervised activity, like preparing a snack or reading a book together.
Let your child know there is never a good reason for hitting, kicking, etc...
Resist asking why he hurt someone. Chances are, he won't be able to explain, and will only be further annoyed by your question.
Reparations are better than apologies. Ask the aggressor to "make it better".
Point out consequences that may result from the misbehaviour.
Anticipate and be prepared to intervene and re-direct your child's aggressive tendencies. It is your responsibility to keep your child's playmates and siblings safe.
Brainstorm some alternatives. E.g.: Provide him with things he CAN throw, kick, or punch.
Hug the aggressor (and the victim too!). Being hugged helps som children to feel they are still loved even though you don't like their behaviour.
Well, the bottom line is that although you cannot stop your child from feeling frustrated, threatened, hurt or angry, you can show him how to express those feelings in ways that do not hurt others.