简介：Theworldwideinterestinthegutmicrobiomeanditsimpactontheupstreamliverhighlightacriticalupsidetobreathresearch:itcanuniquelymeasureotherwiseunmeasurablebiology.Bacteriamakegases[volatileorganiccompounds(VOCs)]thataredirectlyrelevanttopathophysiologyofthefattyliverandassociatedconditions,includingobesity.MeasurementoftheseVOCsandtheirmetabolitesintheexhaledbreath,therefore,presentanopportunitytosafelyandeasilyevaluate,onbothapersonalandapopulationlevel,someofourmostpressingpublichealththreats.Thisisanopportunitythatmustbepursued.Todate,however,breathanalysisremainsaslowlyevolvingfieldwhichonlyoccasionallyimpactsclinicalresearchorpatientcare.Onemajorobstacletoprogressisthatbreathanalysisisinherentlyandemphaticallymutli-disciplinary:itconnectsengineering,chemistry,breathmechanics,biologyandmedicine.Unbalancedorincompleteteamsmayproduceinconsistentandoftenunsatisfactoryresults.Asecondimpedimentisthelackofawell-knownstepwisestructureforthedevelopmentofnon-invasivediagnostics.Asaresult,thebreathresearchlandscapeisrepletewithorphanedsingle-centerpilotstudies.Often,importanthypothesesandkeyobservationshavenotbeenpursuedtomaturation.ThispaperreviewstherationaleandrequirementsforbreathVOCresearchappliedtothegut-fattyliveraxisandofferssomesuggestionsforfuturedevelopment.