Hi Holly, I think it's definitely worth giving calcium a try, I've been taking it for a few months and it does help on a day-to-day basis - I no longer have D every morning. It doesn't seem to help as much though when I get really anxious (holidays etc. when I still rely on Immodium) but I'd still recommend it.It should start taking effect quite quickly so I'd start taking it straight away, I haven't heard of it having any adverse effects on D (as long as you avoid Magnesium.) There's a thread somewhere from LNAPE who can give you all the details.Good luck with the camping!Love G