Bacteria in the large intestine metabolise excess fructose and the products of that metabolism may contribute to increased gas, bloating, abdominal pain, diarrhea and/ or constipation. These are the symptoms most often associated with Fructose Malabsorption. 
According to the biochemical pathway thought to be associated with Fructositis disease, symptoms extend beyond gas related pain and discomfort. Excess fructose is thought to react chemically with dietary proteins to produce digestion resistant fragments. Such fragments may then bind receptors (RAGE) that are known to be heavily concentrated in the lungs and responsible for contributing to inflammation, mucus hypersecretion and airway hyper-reactivity. These receptors are also known to be elevated in autoimmune many auto-immune diseases.