Taking too much of a medicine can be dangerous, and some overdoses cause harm before any symptoms appear, so do not wait to see how you feel. This is especially true for common medicines like paracetamol, where early treatment is vital and delaying can be life-threatening.
If you have taken a large overdose, are struggling to breathe, are drowsy or confused, vomiting, have chest pain, or have collapsed, call your local emergency number or go to the nearest emergency department immediately. Take the medicine packaging with you so staff know what and how much was taken.
For smaller accidental extra doses, contact a poison control centre or your pharmacist for advice on whether you need to be seen. When in doubt, treat it as urgent and get professional help rather than guessing.