Print and Download About Vaping Prevention Resources HHS.gov Vaping and E Cigarettes Causing Outbreak of Respiratory Illnesses, Other Severe Health Problems, and Deaths Sommers Schwartz E cigarettes contain hazardous substances, addictive and harmful Latest Cochrane Review finds high certainty evidence that nicotine e cigarettes are more effective than traditional nicotine replacement therapy (NRT) in helping people quit smoking Cochrane Vaping has become common, but it's important to know what you're inhaling. Many e cigarettes contain nicotine, heavy metals like nickel and lead, and chemicals that can harm your lungs and overall health.