Nux Vomica is a homeopathic medicine. Homeopathics are an interesting branch of alternative medicine and are supposed to work more on an energetic level and tend to be prescribed according to symptom pictures that individuals experience.
I personally have had no luck whatsoever with homepathics, so I am rather skeptical, but they are completely harmless. Either you get a dramatic relief of symptoms from them or nothing happens at all.
O my Father, if it be possible, let this cup pass from me; nevertheless not my will but thine be done. Matt 26:39