Actually the worst I've ever had to put up with was Cod Liver Oil... my mother was a huge fan of the stuff. Apparently her parents tortured her with it when she was a child so she felt it necessary to continue the tradition. Although I must say the stuff actually worked.
All that I've ever really needed was colloidal zinc for my hypozincemia, it tasted slightly of vomit going down because it forced vomit coming up, but that went away with some milk flavoured with honey.
Actually the worst I've ever had to put up with was Cod Liver Oil
Err... Not straight from a Cod I hope. What's that for anyways?