What are 'particulars' and can I demand them from the other side in an Ontario lawsuit?

Particulars are further details about the allegations made in a pleading. If a statement of claim or statement of defence is vague or does not provide enough detail to understand the case you have to meet, you can demand particulars from the other side. This is done formally by serving a demand for particulars.

The purpose of particulars is to ensure that each party knows the case they are expected to answer — so they can prepare their evidence and legal arguments. For example, if a statement of claim alleges "negligence" without specifying what acts or omissions are alleged to be negligent, the defendant can demand particulars of those specific allegations.

If the other side refuses to provide adequate particulars, you can bring a motion asking the court to order them to do so. The court will generally order particulars if the pleading is genuinely deficient and the requesting party would be prejudiced without more detail. However, courts will not use particulars demands as a discovery tool — they are for clarifying pleadings, not for fishing for information that belongs in the discovery process.