Identification of gases responsible for the odour of human flatus and evaluation of a device purported to reduce this odour. "BACKGROUND/AIMS: While the social significance of flatus derives mainly from its odour, previous studies have focused on the non-odoriferous components of rectal gas. The aims of the present study were to determine the role of sulphur-containing gases in flatus odour and test the efficacy of a device purported to reduce this odour. METHODS: Flatus was quantitatively collected via rectal tube from 16 healthy subjects who ingested pinto beans and lactulose to enhance flatus output. The concentrations of sulphur-containing gases in each passage were correlated with odour intensity assessed by two judges. Odour intensity was also determined after treatment of flatus samples with zinc acetate, which binds sulphydryl compounds (hydrogen sulphide and methanethiol), or activated charcoal. Utilising gastight Mylar pantaloons, the ability of a charcoal lined cushion to adsorb sulphur-containing gases instilled at the anus of eight subjects was assessed. RESULTS: The main sulphur-containing flatus component was hydrogen sulphide (1.06 (0.2) mumol/l), followed by methanethiol (0.21 (0.04) mumol/l) and dimethyl sulphide (0.08 (0.01) mumol/l) (means (SEM)). Malodour significantly correlated with hydrogen sulphide concentration (p < or = 0.001). Zinc acetate reduced sulphur gas content but did not totally eliminate odour, while activated charcoal removed virtually all odour. The cushion absorbed more than 90% of the sulphur gases. CONCLUSION: Sulphur-containing gases are the major, but not the only, malodorous components of human flatus. The charcoal lined cushion effectively limits the escape of these sulphur-containing gases into the environment."

We close with one more quote from To the Royal Academy of Farting:

What Comfort can the Vortices of Descartes give to a Man who has Whirlwinds in his Bowels! The Knowledge of Newton's mutual Attraction of the Particles of Matter, can it afford Ease to him who is racked by their mutual Repulsion, and the cruel Distensions it occasions? The Pleasure arising to a few Philosophers, from seeing, a few Times in their Life, the Threads of Light untwisted, and separated by the Newtonian Prism into seven Colours, can it be compared with the Ease and Comfort every Man living might feel seven times a Day, by discharging freely the Wind from his Bowels? Especially if it be converted into a Perfume: For the Pleasures of one Sense being little inferior to those of another, instead of pleasing the Sight he might delight the Smell of those about him, & make Numbers happy, which to a benevolent Mind must afford infinite Satisfaction. The generous Soul, who now endeavours to find out whether the Friends he entertains like best Claret or Burgundy, Champagne or Madeira, would then enquire also whether they chose Musk or Lilly, Rose or Bergamot, and provide accordingly.

Thanks to Tusi for today's ROFL! Related content: Discoblog: NCBI ROFL: Asparagus, urine, farts, and Benjamin Franklin (Part I) Discoblog: NCBI ROFL: It's like a Brita filter for your butt