A dose of a drug which is larger than the recommended or usual dose.
Taking more of a drug than what is normally safe to take.
An excessive and potentially toxic amount of a medication, given in error or taken intentionally (e.g., by patients making suicide gestures or suicide attempts).
The taking of too much of a drug, which causes sickness, loss of consciousness, permanent damage, or even death.
A serious reaction to an excessive amount of a drug that can result in coma or death.