[CliffordK (OP)]

Is Eucalyptus Oil and Menthol bad for a person?  Side Effects?

Ok, so when I get a cold, I tend to like cough drop mints. 

Reading the package of a major brand, its recommended dosage is:

Dissolve 1 drop slowly in the mouth.  Repeat every 2 hours as needed

It seems as if once I suck down half of the drop or so, I get the temptation to crunch it.
Then, 2 minutes later, I'm ready for the next drop.

Is there anything harmful with taking too many?

I have wondered if there is a rebound cough.  Perhaps taking the Menthol drops suppresses a cough temporarily, but causes the cough to be symptomatic for a longer period of time.