Professor Timothy Florin


SOMSouthern - Medicine - Mater Hospital
Faculty of Medicine and Biomedical Sciences
+61 7 3163 8906


The Mater Health Services’ Adult Hospital is a tertiary centre for the treatment of IBD with over 600 patients attending its IBD clinics. Our clinics are linked to a patient research database and laboratories in the Mater Medical Research Institute, Queensland Institute of Medical Research and the University of Queensland’s School of Molecular and Microbial Sciences. Our research covers epidemiology, pathogenesis and treatment of inflammatory bowel diseases

The main research has related to the interactions of diet, microbial flora and human physiology in the normal and inflamed gastrointestinal tract. Working with the MRC Nutrition Unit led by Dr John Cummings, TF initially focused on the influence of dietary and endogenous sulphate on colonic microbial ecology and gas production, which is relevant to colonic health, irritable bowel, colorectal carcinogenesis and IBD.

The Cummings’ group had preliminary data that suggested that dietary sulphate could be linked to bacterial production of the noxious substance, sulphide, through the bacterial metabolic consumption of hydrogen in the colon, and that this might be causal in the pathogenesis of ulcerative colitis. However, it became evident with further research that there was not enough sulphate for bacterial reduction of sulphate to sulphide in the colon, that most colonic sulphide was generated from cysteine and methionine in health and ulcerative colitis, and that there were quantitatively more important ways in which colonic bacteria disposed of hydrogen gas. Research on hydrogen disposal by colonic bacteria and physiological gas exchange led to improved understanding of colonic gas pathophysiology. In particular, two papers on pneumatosis cystoides coli, a disease that we established was caused by impaired hydrogen gas disposal, were published in Lancet and Gut. They completely solved the major aspects of the pathogenesis of pneumatosis cystoides intestinalis and the treatment of this hitherto very enigmatic disorder.

One of the main routes for bacterial disposal of hydrogen is via methanogenesis. Methanogens reduce carbon in carbon dioxide to hydrogen. This is universal in rumen physiology but only occurs in some colons or animal hindgut. My work has indicated a major role for bile acid, the major sink product of cholesterol and metabolite important for fat absorption, in determining hydrogen disposal by methanogens. This as well as other factors associated with the complex colonic microbial ecology, some genetic and some environmental, determine the presence of methanogens. The last mentioned study also illustrated the stability of the colonic microbial consortium once established after weaning, by its resistance to colonisation with new microbial organisms.

The research into colonic microbial ecology has become in the last six years very focused on IBD – (I have a large IBD practice. Its pathogenesis to this day remains enigmatic) - and ‘molecular’, with the realisation that specific intestinal mucosal bacteria are likely to have a major role in determining IBD, and that these bacteria cannot be easily identified by conventional culture methods. This research is starting to bear fruit.

This IBD research is coupled with research into clinical, epidemiological, genetic and therapeutic aspects of IBD. Together with Dr Graham Radford-Smith, I have established a large and detailed IBD register, which combines detailed phenotypic and environmental information with a serum, DNA and biopsy bank. The collaborative resource is the clinical platform for the laboratory-based research. This resource has been pivotal in facilitating the translation of our clinical and laboratory research into new therapies.

The IBD Research Team at Mater is currently focused on:

  • discovering the mucosal bacteria that in large part determine the normal physiology of the intestine, as well as the pathogenesis of IBD
  • understanding the pharmacology of drugs that are used to treat IBD
  • discovering the major environmental factors that may be important in IBD
  • elucidating the mucous barrier that is the first line of defence against infection by gastrointestinal mucosal bacteria


  • MBBS (Honours), The University of Sydney
  • Master of Science, The University of Sydney
  • Bachelor of Science (HMS), The University of Sydney


View all Publications


Book Chapter

  • Florin, T. H. J. (2006). Disturbances in microbiota - cause or effect?. In Fraser, A., Gibson, P. R., Hibi, T., Qian, J. M. and Scholmerich, J. (Ed.), Emerging Issues in Infammatory Bowel Diseases (pp. 79-82) Sydney: Springer.

Journal Article

Conference Publication

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

Completed Supervision