In general, the EPC allows both method claims and use claims, but whether an activity is claimed as a method of carrying out the activity (setting out a sequence of steps) or as the use of a thing for a stated purpose (the sequence of steps being implied) is a matter of preference. For the Enlarged Board of Appeal there is no difference of substance (G 5/83, OJ 1985, 64).

The Enlarged Board dealt in detail with the novelty of second non-medical uses in G 2/88 (OJ 1990, 93) and G 6/88 (OJ 1990, 114). The questions referred to it concerned use claims, i.e. claims defining a "use of compound X for a particular purpose", or similar wording, where the only novel feature was the purpose of that use. They were not about medical inventions but were of a general nature and primarily concerned interpretation of Art. 54(1) and (2) EPC 1973. The patentability of a second non-medical use of a product had already been recognised in principle in G 5/83 (OJ 1985, 64), which concerned the second medical use of a substance.

In the non-medical field use claims are admissible and not subject to special conditions.

In G 2/88 (OJ 1990, 93) and G 6/88 (OJ 1990, 114), the Enlarged Board had to decide whether a claim for the use of a compound for a particular non-medical purpose was novel under Art. 54 EPC 1973, having regard to a prior publication which disclosed the use of that compound for a different non-medical purpose, so that the only novel feature in the claims was the purpose for which the compound was used. The specific problem in these cases was that the previously disclosed use of the substance, although specifically stated to be for another purpose, would inherently comprise the use as claimed in the new application (T 59/87 date: 1988-04-26, OJ 1988, 347; T 208/88 of 20 July 1988 date: 1988-07-20).

The Enlarged Board cited T 231/85 (OJ 1989, 74), a case concerning an application for use as a fungicide of a compound already disclosed in the prior art as a growth regulator. The use according to the claimed invention and the use disclosed in the prior art were both carried out in the same way (i.e. the means of realisation was the same, namely the spraying of useful plants). The board had nevertheless concluded that the claimed invention was novel because the technical teaching in the application differed from that in the citation, and that, even if means of realisation was the same, the use was not yet known.

In G 2/88 and G 6/88, therefore, it was pointed out that a claimed invention lacked novelty unless it included at least one essential technical feature which distinguished it from the state of the art. A basic initial consideration, when deciding upon the novelty of a claim, was therefore to analyse it in order to determine its technical features. The Enlarged Board took the view that the proper interpretation of a claim whose wording clearly defined a new use of a known compound would normally be such that the attaining of a new technical effect on which the new use was based was a technical feature of the claimed invention. Thus, where the particular technical effect underlying such use was described in the patent, the proper interpretation of that claim would require a functional feature to be implicitly contained in the claim as a technical feature – e.g. the compound actually achieved the particular effect.

The Enlarged Board thus concluded that, with respect to a claim to a new use of a known compound, such new use might reflect a newly discovered technical effect described in the patent. The attaining of such a technical effect should then be considered as a functional technical feature of the claim (e.g. the achievement in a particular context of that technical effect). Had that technical feature not previously been made available to the public by any of the means set out in Art. 54(2) EPC 1973, then the claimed invention was novel, even though such technical effect might have inherently taken place in the course of carrying out what had previously been made available to the public. The final decisions in cases T 59/87 date: 1990-08-14 (OJ 1991, 561) and T 208/88 date: 1990-02-28 (OJ 1992, 22) both held that the claimed use inventions were novel and inventive.