As I understand it theoreticallly there is a risk but no one in the trials actually had a reaction to foods with the risk substance in them (ty.......can't remember the name) and anyway the usual dose is very low. I was very nervous but have no side effects whatsoever and do feel that it has smoothed out the effect of the sinemet I am on. Bonus might be neuroprotective effect but that as far as I know is not universally accepted. I have read about others who felt it wasn't doing it but when they stopped they realised it was lengthening the on times. Its quite a subtle effect.