The suspension is then strained through a filter and transferred to an administration container. If the suspension is to be used later, it can be frozen after being diluted with 10% glycerol, and used without loss of efficacy compared to the fresh sample. The fecal transplant material is then prepared and administered in a clinical environment to ensure that precautions are taken. After being made into suspensions, the fecal material can be given through nasogastric and nasoduodenal tubes, or through a colonoscope or as a retention enema. One hypothesis behind fecal microbiota transplant rests on the concept of bacterial interference, i.e., using harmless bacteria to displace pathogenic organisms, such as by competitive niche exclusion. In the case of CDI, the "C. difficile" pathogen is identifiable. Recently, in a pilot study of five patients, sterile fecal filtrate was demonstrated to be of comparable efficacy to conventional FMT in the treatment of recurrent CDI. The conclusion from this study was that soluble filtrate components (such as bacteriophages, metabolites, and/or bacterial components, such as enzymes) may be the key mediators of FMT's efficacy, rather than intact bacteria. It has now been demonstrated that the short-chain fatty acid valerate is restored in human fecal samples from CDI patients and a bioreactor model of recurrent CDI by FMT, but not by antibiotic cessation alone; as such, this may be a key mediator of FMT's efficacy. Other studies have identified rapid-onset but well-maintained changes in the gut bacteriophage profile after successful FMT (with colonisation of the recipient with donor bacteriophages), and this is therefore another key area of interest. In contrast, in the case of other conditions such as ulcerative colitis, no single culprit has yet been identified. However, analysis of gut microbiome and metabonome changes after FMT as treatment for ulcerative colitis has identified some possible candidates of interest. The concept of treating colon diseases with fecal matter originated in India. Charak Samhita and many other ancient Ayurveda text that date back to more than 3,000 years recommend intake of cow dung and cow urine for multiple stomach-related disorders. Fourth-century Chinese medical literature also mentions use of fecal matter to treat food poisoning and severe diarrhea. Twelve hundred years later Ming dynasty physician Li Shizhen used "yellow soup" (aka "golden syrup") which contained fresh, dry or fermented stool to treat abdominal diseases.