Entacapone also known as Comtan or Comtess, and Stalevo are known to cause diarrhoea (It is in the side-effects leaflets). When this happens it is recommended to discontinue the medication as the problem is unlikely to resolve. If you are on one of these medications it might be a good idea to consult your neuro. I was advised of this when I was started on entacapone.

Hoping you find a good solution to your problem

Lindy