Lamberts fos formerly known as eliminexr r fosconsists of a special kind of pure soluble fibre called fructo oligosaccharide fos which helps carry moisture through the digestive systemr r uses fructo oligosaccharides fos a form of soluble fibre is found in many vegetables such as chicory and onions this natural compound can only be partially digested by humans with the undigested portion serving as a food for the friendly bacteria such as bifidobacteria and lactobacillus speciesr r th