
Pedigree Complete that you get in the stores etc is full of colourants, additives, preservatives and just general rubbish to be honest. If you wanted to keep to a dry complete diet then I'd consider one of the hypo-allergenic brands such as JWB, Burns, Arden Grange, Wainwrights etc (there are many of them). With regards to the many tinned/wet foods, there are a few decent ones such as Naturediet, naturesmenu to name a couple (there are others which names escape me of present) And then again as MariaC said there is the BARF diet to which you can be sure exactly what you are feeding...
so as you can see, there are many options, just a case of finding which food suits your dog best really, though with the upset stomach thing i'd lean towards one of the more natural diets :)