Just wondering if it is quite common for dogs to get bouts of vomiting/diarrhoea regularly - I mean every 2 or 3 weeks. Honey has always tended to be like this (she is 3 now) and I am sure she never eats anything funny on a walk. I also don't really think it is dietary related because she is fine in between episodes. But I do think she often seems quite lethargic though that may be unconnected. I'd be interested to hear if this is usual.

never had that with any of mine.

er... i would say that that sounds a bit like me though... i do have a bowel problem. not trying to be an alarmist and obviously your dogs guts are different from mine but if its frequent i'd want to get that checked.

my boy was like this, I thought he had IBS so got the vet to check everything including allergies.  As it turned out he is intollerant to chicken and duck, with this cut out of his food he hasnt had a problem since. 

> Just wondering if it is quite common for dogs to get bouts of vomiting/diarrhoea regularly

It can be common in some breeds, GSDs spring to mind and some individuals have very sensitive stomachs. However it should not be thus and perhaps it needs looking into, may be asking the owners of the litter mates if they are having problems, it could be one of those things that runs in some lines. (Pun not intentional but too late to think of a better word.)

Are you giving any treats etc?  A puppy owner of mine was giving a certain dog teeth treat every day, told them to stop it and he was fine afterwards.  This was after 8 months of going to the vets for different tests!

I had  a similar problem and discovered that turkey was the problem.

> I also don't really think it is dietary related because she is fine in between episodes.

But it can be. One of mine would be sick now and again, couldn't find anything wrong with her at all, checked out at the vets, all fine. Changed her diet (two years ago now) not been sick since.

Hmm I am thinking hard about her diet now. I realised a while back that she gets diarrhoea if she eats fatty bits of meat, but I do add lean meat to her complete to make it more interesting. I vary the meat depending on what we are having. Just before this upset tummy I had given her some beef - wonder if that could cause a problem? She also gets tripe sticks sometimes and little puppy bones for training treats.

I would start with an exclusion diet.

First week give her only her complete, no treats of any kind at all (use her dry food as treats).

If all is well then re-introduce one of the treat types and see how it goes after a week or two, and negative results like looser poo, and you have your answer.

If none of this helps, then you may need to change her whole diet to something she will never have eaten before (a different meat and different carbohydrate source).

This could be for example white fish and Cous cous, if she has not eaten these before.

An exclusion diet does sound like very good advice (though hard!)
I am sure it is in her interests because she gets quite miserable when she is sick. I think she has quite a delicate tummy, I did once try giving her some white fish (cooked) and she was really sick straight away. Her complete food is Pro Plan, I will do as you suggest and try giving her only this, but I expect there are complete foods developed for dogs who are sensitive too.

With any commercial diet there are lots of ingredients any one of which she could be sensitive to.

The idea behind an exclusion diet is to feed something she has not had before, so no to the fish then.

You would need to give her something that isn't in the food she is on now or the treats or extras.

My dog has it, and as you said it often happens once every couple of weeks. It doesnt seem to bother him too muc. hes on a very good diet. I just put it down to one of those things and think he suffers a weak stmach although he is on a gluten free diet (although dont think that make too much difference)

have had something very similar with my WSD and had tried various complete diets.  I have finally found Genesis complete, he has been on it now for 3 months and we have not had one bout of illness since being on it. 

Yes I had this with my rottie xgsd.  Then I put her on tinned chappie chicken and rice and she has never had another bout of it.