EDITORIAL Does cannabis use predispose to chronic airflow obstruction?

sativa, and also known as marijuana) is the most widely used illicit drug worldwide, as well as the second most commonly smoked substance after tobacco, with an estimated 166 million users (3.9 % of 15–64 yr olds) [1]. Its wide popularity is due to the euphoric effects of its major psychoactive ingredient, D9-tetrahydrocannabinol (THC). Since the gas and particulate phase constituents of the smoke of marijuana are at least qualitatively similar to those of tobacco, the major exception being the nicotine in tobacco and the,60 cannabinoid (THC-like) components in marijuana [2, 3], there has long been concern that regular smoking of marijuana might increase the risk of developing chronic airflow obstruc-tion and chronic obstructive pulmonary disease (COPD), by analogy with the well-known detrimental effects of tobacco. Several studies have documented that smokers of marijuana