Durian has a gene called MGL that produces sulfurous volatile compounds, which give durian a moderate to strong acrid smell, depending on the variety of species. Those who dislike it may feel queasy and lightheaded, while those who enjoy it find the aroma exotic and enticing to eat. Due to the strong, pungent smell of durian, many public transportation systems and venues, including airplanes, trains, hotels, and theaters, have to put up signs prohibiting durian from being onboard or on-premises.