In the European patent system, within nine months everybody can file an opposition against grant of an European patent. The grounds for opposition are specified in Article 100 EPC. The opposition procedure is quite inexpensive, compared to a nullity action before a national civil court. Since all parties have to carry their own costs, independent of the outcome of the case, the opposition procedure furthermore comprises only a very limited financial risk.

After the expiration of the nine months opposition period, the European patent cannot be attacked any longer in one central procedure. A third party may then have to make use of the different legal measures provided by the applicable national legislations, such as nullity actions. Since these procedures are in most cases expensive and longsome, it is of utmost importance to attack (potentially) troublesome European patents using the central and inexpensive opposition procedure. If necessary a European patent application may already have to be monitored in the examination phase, in order to know as early as possible the date of grant and the end of the opposition period.

Since 1 July 2008 the Swiss patent law comprises the possibility of an opposition against a granted Swiss patent. Everybody may file an opposition, within nine months after the registration of the grant of the patent. However, the opposition may only be based on the fact that the object of the patent is excluded from patentability under Art. 1a, 1b, or 2 Swiss Patent Statute. For example a patent may not contravene public order or morale. Specifically excluded objects are for example parts of the human body in their natural surroundings. Essentially the aim of the Swiss opposition procedure is to provide an inexpensive way to attack patents that contravene public interests.

No ground during examination or opposition is, however, lack of novelty or inventive step. If somebody wishes to take action against an invalid Swiss patent, he thus will still have to file a civil nullity action with the Federal Patent Court.