just had an unfortunate encounter with a green slime after being waylaid by a cockatrice, you're starving to death and accidentally ate some tainted meat, you're infected with lycanthropy, and to top it all off you've just put on an amulet of strangulation. Is this the end? Maybe not.

Petrifying - Eat a lizard corpse, or any acidic corpse that isn't too old. Also, you can polymorph into a cockatrice, a stone golem, an acidic monster, or another version of yourself. Also, if your god is happy with you, you can pray.

Slimed - Read a scroll of fire; although this will cause you some damage and possibly burn your scrolls and spellbooks, it will burn off the slime. You can also zap yourself with a wand of fire, step on a magic trap, or get something else (such as a pyrolisk) to attack you with fire. Prayer will also help.

Sick - Apply an uncursed or blessed unicorn horn, polymorph into a unicorn and use #monster to heal yourself, quaff a potion of extra healing or a potion of full healing, cast cure sickness on yourself, polymorph into a new self, or pray. An unlikely approach is to eat a rotten egg, which will induce vomiting.

Lycanthropy - Eat a sprig of wolfsbane, polymorph into a new self, quaff a potion of holy water, or pray.

Starving - Pray. If unable, cast stone to flesh on nearby rock, which you can always create by digging with a pickaxe or reading a scroll of earth.

Strangled - Pray if able, otherwise attempt to uncurse the amulet by the usual methods.