Is there any medicine to make a weed smoker quit ?

it is not that difficult, i smoke both and recently stoped for a week ( i smoked daily for almost 3 years ) and it wasnt bad at all, i honestly craved a cig way more... its will power, tell him/ her how you feel , if he / she doesnt want to quit, leave them alone, its not that bad of a habit, if he/ she is down to give it a try, tell them to gradually stop.. not cold turkey, even though its not that bad like i said before...