Paul, u seem to make a valid point - that this "smelly anus" is brought about as a result of localized infection elsewhere. I had always had very discolored toe nails (a probable sign of fungal/yeast infection) but i didnt start having a "smelly anus" until I started stepping on other's people urine frequently while constantly using a particular badly maintained school bathroom stall. I remember my odor problem first starting through my shoes. The shoes i was wearing to step on another person's urine on the bathroom floor started to smell like onions, sulphur_like... In a short period, my anus began to smell strong of feces and i also smell strongly of any food i eat. perhaps, the odor bacteria got transferred into my colon from my feet as a result of my constantly stepping on another person's urine.