It identifies the release
Products with the same name may be packaged at different times or belong to different production runs. The lot number helps distinguish the exact release.
It supports product questions
If you contact a producer or retailer, the lot number helps them understand which package you have. Keep the original package and share the number exactly as printed.
It belongs with the label
A batch number is most useful alongside the product name, package date and other label details. Together, those fields provide the clearest reference for a question.
Keep exploring
Reference: Health Canada: How to read and understand a cannabis product label. Collection and availability details refer to the Dom Jackson product library; retailer stock can change.