What Happens When You Swallow Vape Juice? Even if you dont inhale while vape smoking, your mouth, throat, and lips are exposed to harmful chemicals, as is your oesophagus when you swallow saliva that contains the chemicals. , There is a Kids Health Info : Vaping and e cigarettes If you vape, you inhale a lot of harmful substances. These can damage your heart and lungs. I'm ingesting liquid when vaping: How to Avoid It