In an action before the Court of the Commissioner of Patents, the plaintiff sought an interdict restraining the defendants from infringing or aiding and abetting the infringement of a patent of which he was the proprietor. The defendants denied that they had infringed the plaintiff's patent through the use of the plaintiff's invention in their products or services, and claimed further that the patent was invalid for lack of novelty and for being obvious. Held Section 45(1) of the Patents Act 57 of 1978 ("the Act") provides that the effect of a patent is to grant the patentee, for the duration of the patent, the right to exclude other persons from making, using, exercising,disposing or offering to dispose of or importing the invention defined in the claims of the patent, so that he will enjoy the whole profit and advantage accruing by reason of the invention. In order to decide whether the defendants' products and services infringed the patent, the Court had to determine what the essential features of the claims of the patent were. If all the essential features of the claim were present in the targeted products of the respondents, the conclusion would be that the patent was infringed. In other words, whether or not a plaintiff has proved an infringement of his patent turns upon a comparison between the article or process, involved in the alleged infringement and the words of the claims in the patent. The onus was on the plaintiff to prove infringement. The Court set out the correct approach to interpreting a patent for the purposes of determining infringement or invalidity. It pointed out that our law of interpretation has moved beyond an over literalist approach. In this case, the plaintiff was unable to discharge the onus resting upon him, and the action-based noninfringement was dismissed. The next issue addressed by the Court was the defendants' claim of invalidity. In that regard, the defendants alleged that the patent was not new in that it formed part of the state of the art immediately before the priority date of page 382 of [2009] 1 All SA 381 (T)claims to the invention. The evidence adduced bearing out the defendants' allegation, the Court upheld the argument on this point. Finally, the issue of invalidity through lack of an inventive step was addressed. An invention is only patentable if it involves an inventive step. An invention shall be deemed to involve an inventive step if it is not obvious to a person skilled in the art, having regard to any matter which forms, immediately before the priority date of the invention, part of the state of the art. Again, the defendants' argument was sustained by the Court. The plaintiff's action was accordingly dismissed, and the defendants' counterclaim upheld