In order from horribly gross to #1 most disgustingly grossest:

4. A mouthful of gasoline onceupon a time when attempting to siphon from a gas can to a generator. I didn't swallow it completely, but I got enough to know I didn't want any more.

3. Liquid barium contrast medium for an upper-GI series X-ray. Repulsive, but more due to the texture than the actual taste.

2. A combination pickle-juice, yard dirt, tree-leaves (elm), canned cat food and melted butter mixture I was required to swallow as part of an 11-year-old Halloween truth-or-dare which I stupidly took the dare option on.

1. A fertility-vitality tonic tea that was brewed for me in San Francisco's Chinatown by a Taiwanese herbalist when I was hoping to get pregnant with a second baby. I don't know what was in it, but it tasted like a cocktail of bile, lake water, rotten blue cheese, snails, and yard compost. Disgusting to the last drop.