Long time lurker, first time poster.
For making me want to barf, either the story scene in Stand by Me, or the Blair Witch snot spoof in Scary Movie. (Though Scary Movie 2 also contains something barf worthy. THE WHOLE PRODUCTION.)
As far as disgusting me on a deep level, Urotsudoji: Legend of the Overfiend fills me with bile and disgust.
I KNEW something was up when a young just in the Navy Bloodcat took the VHS tape up to the Suncoast counter because I heard in a videogame magazine that it was supposed to be really gross, and the clerk looked at me kind of funny and told me once I opened it, I could not return it, something they had not done when I bought my first anime tapes there, mostly Robotech and the other few releases there were in 1993. (I figured gross meant all bloody and "cool" like the Image comic books of the time, or like Alien or the Return of the Living Dead flicks. I had my gore phase.)
However, going to the barracks and watching the film let me find out what it really was. The most offensive, demeaning, and just plain HATEFUL movie I had ever seen.
In a nutshell the movie wants to tell us this: We hate everyone. We hate women even more you filthy (Insert your own vulgarity here.).
Little did I know that this was actually on the LOW end of some of the anime/manga/live action scale of "entertainment" in Japan.
Thankfully, I have been able to avoid most of the sicko stuff, but a few jpgs and the like have sadly caught my eye, making me want to stab it out...