Since when have you had this craving?
DO you have any dental problems or problems in smel?
Do you get regular periods?
Craving for a certain type of food is believed to be due to a desire to satisfy oneself with oral stimulation. In psychological terms , it is called 'Oral Fixation'. It is said to be a part of a personality that feels deprived in some way and tries to overcome this deprivation by oral stimulation.
'Oral Fixation' is a part of Freud's personality theories - many of these theories are disputed now.
In your case, it is likely that you simply enjoy the taste of peppermints and feel a rush of 'feel-good' sensations when you take them. This then fuels the desire for more peppermints.
You can read more about Freud's theories here:
I hope this helps.