Many secondary metabolites of plants have medicinal properties

Many secondary metabolites of plants have medicinal properties. It is their misuse that creates problems. Justify the statement with an example.

Many secondary metabolites obtained from plants are used for their’medicinal properties, e.g. opiates derived from poppy plant are used as drugs to relieve pain.
The problem starts when these metabolites are misused for having pleasure and are taken in doses above the prescribed limit, e.g. opium addict- loses wight , fertility and interest in work.