At normal dosages, Panadol is a common and effective pain reliever. According to DrugBank, the drug is metabolized by the body into a toxic compound called NAPQI that is excreted through the kidneys. Panadol has a very short half-life, meaning that it is excreted by the body quickly. However, at high dosages the body cannot get rid of the toxic metabolite fast enough. This causes liver damage and potentially death. PubMed mentions that symptoms of overdose manifest in the form of internal bleeding indicated by tarry, black stools and vomit that resembles coffee grounds.