This is a very common problem with formula, particularly the soy based variety. If formula is a necessity, I'd make sure to get the milk based ones. Some of the organic companies (Horizon and a couple of other organic baby food companies) are making formula now. I never used any formula, but I did notice in comparing them that the ingredients list on the organic products were much shorter and that's usually a good thing! Also, I noticed you mentioned staying away from apple. Unless there is an allergy issue, I'd use a little bit of apple juice here and there. Apple juice, like prune juice, can function as a mild laxative. Especially if you stick with the real, unfiltered apple juice and stay away from the filtered concentrates that are lower in vitamins and fiber, and higher in sugar. The last thing I can think to check on the iron content in his diet. If the stool is dark and hard when it is produced, that can be a sign that there is too much iron in his diet. If this symptom is present, mention it to your doctor and check the iron content on his formula and any other supplement products you are giving him. You may need to stop using them, or reduce the amount he is having. Although they may help in some situations, I'd refrain from using enema products on such a little one without direction from your doctor. Good luck with your little guy. I hope this helps...