South Africa, just like many other countries, has a set of legal provisions pertaining to subject matter for which patent protection may not be obtained.

For example, and relevant for present purposes, in terms of section 25(11) of the South African Patents Act ("the Act"), inventions which are directed to methods of treatment on the human or animal body by surgery or therapy or of diagnosis practised on the human or animal body are not allowed to be claimed in South African patents.

In order to address the prohibition on claiming, as a method of treatment, subject matter distinguished in its usefulness in a method of treatment performed on the human or animal body by surgery or therapy or of diagnosis, and thus still obtain protection for inventions that are distinguished in such usefulness, South African patent law and practice allows the claiming of therapeutic/prophylactic/diagnostic medical purpose-limited novel or known substances or compositions distinguished in a first medical uses, in claims in the format "A [compound or substance] for use in a method of [therapeutic/prophylactic/diagnostic treatment practiced on the human or animal body in respect of a particular disease or condition]" and, furthermore, allows the claiming of the use of known substances or compositions in the manufacture of pharmaceutical compositions or medicaments distinguished in a second or subsequent medical use of the substance or composition, in the so-called Swiss form.

The abovementioned exclusion of methods of treatment practiced on the human or animal body from patentability of course applies only in respect of such methods where they have a therapeutic/prophylactic/diagnostic effect. If a method practiced on the human or animal body does not have such an effect, it would implicitly be patentable.

But what about situations in which a method that produces a non-therapeutic/prophylactic/diagnostic effect may also produce a therapeutic/prophylactic/diagnostic effect?

Cosmetic compositions used in methods of treatment of the human or animal body to produce a cosmetic effect is one area of interest in this regard. Of particular interest, are claims drafted as methods of treatment to produce a cosmetic effect. If one considers only their cosmetic effect, such methods of treatment claims are generally patentable, but this is only conclusively so provided that the method does not have a therapeutic/prophylactic/diagnostic effect.

There are, however, quite often situations in which a cosmetic composition could, when used in a method of treatment to produce a non-therapeutic (cosmetic) effect, have an incidental therapeutic/prophylactic/diagnostic effect, which effect may in some cases be inextricably linked with the non-therapeutic effect.

Examples may include cosmetic compositions which have a non-therapeutic effect of inducing weight loss and an inseparable therapeutic effect of treating obesity. In such cases it may be arguable that the claiming of a method of producing a cosmetic effect would encroach on the section 25(11) prohibition of the Act and thus be deemed invalid/unpatentable in South Africa.

While this matter has been addressed in a number of foreign jurisdictions, our courts are yet to be given an opportunity to provide guidance thereon.

In the absence of judicial guidance and to obviate any debate on whether the non-therapeutic effect of a cosmetic method of treatment claim may be inextricably linked with its therapeutic/prophylactic/diagnostic effect, where there is or may be such a therapeutic/prophylactic/diagnostic effect, our advice would generally be to avoid the claiming of methods of non-therapeutic (cosmetic) treatment where there may be an incidental therapeutic/prophylactic/diagnostic effect associated with such a method and rather to rely on purpose-limited compound and/or Swiss form claims.

While the development of South African patent case law on this matter is awaited, it is therefore believed to be advisable for prospective patentees to weigh the enforcement benefit of cosmetic method of treatment claims up against the possibility of their invalidity in light of any possible incidental therapeutic/prophylactic/diagnostic effect and to consider prosecuting, instead, purpose-limited compound and/or Swiss form claims in such cases.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.