Since it first appeared on UK shelves in 1956, paracetamol has become the nation's default painkiller - swallowed for everything from headaches and toothache to back pain and fever.
Millions of Americans pop these pills like candy, unaware they are causing silent damage, with doctors now warning that coming off them can be a nightmare.
A deadly illness once thought to be left behind in ancient history is making a comeback as it mutates to become more resistant to even the most powerful modern-day drugs.
Hit by daily episodes of dizziness, fatigue and nausea, Tracey Condron thought she had a virus. But alone at home, four months later, things suddenly took a turn for the worse.