According to an IMDb fan vote, 10% of the Top 250 Greatest Films of All Time have drug themes:
4. Pulp Fiction
13. One Flew Over the Cuckoo's Nest
15. GoodFellas
19. The Matrix
21. City of God
34. Apocalypse Now
42. Modern Times
55. American Beauty
66. A Clockwork Orange
77. Requiem for a Dream
79. Once Upon a Time in America
84. L.A. Confidential
88. Monty Python and the Holy Grail
94. 2001: A Space Odyssey
125. Scarface (remake)
132. The Big Lebowski
133. Touch of Evil
137. Lock, Stock & Two Smoking Barrels
144. Platoon
149. Trainspotting
150. The Wizard of Oz
158. Annie Hall
166. Life of Brian
183. Donnie Darko
191. Black Swan