Detect Poison

(Player's Handbook v.3.5, p. 219)

Level: Cleric 0, Urban Druid 0, Death Master 0, Sha'ir 0, Wu Jen 0, Court Herald 0, Blighter 0, Healer 0, Wizard 0, Sorcerer 0, Druid 0, Nentyar Hunter 1, Ranger 1, Paladin 1, Assassin 1, Death Delver 1,
Components: V, S,
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Target: One creature, one object, or a 5-ft. cube
Duration: Instantaneous
Saving Throw: None
Spell Resistance: No

You determine whether a creature, object, or area has been poisoned or is poisonous.
You can determine the exact type of poison with a DC 20 Wisdom check.
A character with the Craft (alchemy) skill may try a DC 20 Craft (alchemy) check if the Wisdom check fails, or may try the Craft (alchemy) check prior to the Wisdom check.
The spell can penetrate barriers, but 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt blocks it.