606 is a leading Supreme Court of Canada decision on section 7 of the Canadian Charter of Rights and Freedoms and the doctrine of vagueness.

A number of pharmacies were charged with conspiracy "to prevent or lessen competition" under section 32(1)(c) of the Combines Investigation Act for the sale of prescription drugs and dispensing services prior to June 1986.

At trial, the Supreme Court of Nova Scotia found in favour of the pharmaceutical companies and overturned the conviction.

A law will be in violation of section 7 for vagueness if "it so lacks in precision as not to give sufficient guidance for legal debate."

(p. 636) The term "legal debate" was intended to reflect and encompass the principles of vagueness in the "fuller context of an analysis of the quality and limits of human knowledge and understanding in the operation of the law."