To me it smells like the campfire and beans portion of Blazing Saddles would smell. It's horrid and gets into your nose for far too long.
I do have a remedy for the evil Houttuynia for those who want to eliminate it. Took me years and years of digging in vain but...Ortho's Poison Ivy and Tough Brush Killer, used WITHOUT diluting, and sprayed only on the Houtt. leaves, in sunshine, around 65 degrees or more, will kill it. Please protect all good plants or they'll get killed as well and don't spray on a windy day.
It is not a job for a tank sprayer!
Buy the concentrate but do not dilute it.