Teen smokers most likely to combine conventional tobacco and e cigarettes E cigarettes are not a healthier alternative to cigarettes. They contain nicotine and many harmful ingredients that can cause cancer and heart disease. Since these products are relatively new, we don't know all E cigarette use among youth in the US declined to the lowest level in a decade CNN E cigarettes and smoking cessation among adolescent smokers Scientific Reports 5 Surprising Ways E Cigarettes Impact Neuro Health