That Nystatin doesn't work for an intestinal candidiasis. Is it sweet ?? If so, it is loaded with sugar, and please, don't take it. It will do more damage than help. The best Nystatin form to combat candida is refrigerated powder. Second, tablets of 500 000 units. Oral solutions loaded with Sugar don't work. There is no place online I am aware of that sell Nystatin refrigerated powder without scrip. Even the tablets from Canada, you will need an scrip. By the time you get the right Nystatin, you can use SF-722 (undecenoic acid). It is totally safe and very close to a Rx antifungal. It is the main ingradient of several antifungal compounds such as Desenex. It is probably more effective than Nystatin for an intestinal overgrowth. You also can use liquid Caprylic Acid. (liquid, no capsules) About your son, you have to be careful with the doses. I am not sure what are the right dosage for him. Don't believe too much in the Dr. Semon system. I find his diet no the best option to treat a fungal intestinal overgrowth. It all depend of how severe the infection is. He also have Nystatin overrated. It is a good medicine but there isn't monotherapy that can win against candida, at least oral versions. Not sure if IV Echinocandins end with the infection since they are mostly fungicidal.