A treatment method that is patentable in the US may not be patentable in Europe. In fact, European patent laws (as opposed to court interpretations of patent law like in the US) specifically exclude human treatment methods from patentable subject matter.
Colgate's mouthwash is an example.
Colgate's patent application was for a “dual phase” mouthwash having a hydrophilic (water attracting) phase and a hydrophobic (water repelling) phase.
The mouthwash also contained a hydrotrope that tends to make hydrophobic compounds dissolve in water. The claimed hydrotrope was glycerin and/or propylene glycol which are “humectants”.
The patent application additionally included a claim to a method of improving oral health by using the dual phase mouthwash.
As to the method claim, the European patent board noted that it was of a “therapeutic nature” and considered it a method for treating a human or animal. The Board concluded that such a method was excluded from subject matter that could be patented.
The Board went on also reject Colgate's argument that the claimed “humectants” were limited to glycerin and/or propylene glycol. Indeed, the specification also mentioned a third compound as a possible humectant.
The Board concluded that the claimed mouthwash lacked an inventive step. In other words, in US parlance, it was obvious in view of the prior art.