Ondansetron
"I use ondansetron orally disintegrating tablets that i receive via prescription (8mg). I only use these on rare occasions when i eat badly, eat too much, or am very anxious, thereby making myself sick. It usually kicks in a few hours after i take it. (They are disintegrating but I usually swallow them with water because the taste is unappealing to me, but so far that has not affected its efficiency). Every time as far back as i can recall (and I have been taking this for several years) this medicine has been able to help with my nausea and vomiting. The only times i remember getting sick despite the medicine was when i got upset and cried violently, causing me to throw up. Other than that i don't recall ever throwing up after taking it!"