Some interactions are weird to me like why eating a lizard corpse in NetHack stops stoning. Other actions like wielding a potion in ADOM to hit with it make more sense. Some are funny. In ZapM drinking beer banishes fear (liquid courage).
The thing with lizard corpse is that it's acidic (supposedly), and acid stops stoning. Once you know that, you can use several ways to apply acid on yourself. Similarly, fire stops you from turning into a green slime. One of my favorite things that you can do in Nethack is polymorphing into a cockatrice, laying eggs, and them throwing them at monsters to turn them into statues instantly. You can wield potions in Nethack too, btw.
In Crawl when poison resistant you can drink potions of poison as sustenance.
You mean they have a healing effect?