Advil (Ibuprofen) overdoses have many possible symptoms.
Ringing in the ears, Blurred vision, Diarrhea, Heartburn, Nausea, vomiting (sometimes bloody), Stomach pain (possible bleeding in stomach and intestines), Low blood pressure (shock) and weakness, Little to no urine production, kidney shutdown, Breathing difficult and slow, wheezing, Agitation, confusion, incoherent (not understandable), Drowsiness, even coma, Convulsions, Dizziness, Headache (severe), Unsteadiness, trouble moving, skin rash, sweating, chills
It can kill a person if enough is taken, or may just lead to permanent damage of the brain or kidneys or liver. A person may want to die in an overdose because of the long lasting effects.
Melatonin is a naturally occurring hormone in the body that helps regulate the sleep cycle. It is produced by the pineal gland in the brain. Overdose symptoms are crankiness, headaches, dizziness, upset stomach, diarrhea, joint pain, anxiety. It would take a lot of it to actually kill a person and more likely that person would just feel incredibly bad.