Free World Trust v Électro Santé Inc, [2000] 2 S.C.R. 1024, 2000 SCC 66, is a leading Supreme Court of Canada decision on patents, namely claim construction and the necessity to identify essential elements and non-essential elements. Along with the related decision, Camco v. Whirlpool (2001), 9 C.P.R. (4th) 129 (SCC), the Supreme Court of Canada rejected the doctrine of equivalents applied in the United States and adopted the doctrine of purposive construction, as originally applied by the United Kingdom House of Lords in Catnic v. Hill & Smith. This was a landmark decision as it resolved the uncertainty in Canadian case law between the two doctrines.