Spitting after smoking?

The other day I told my friend off really bad because she was smoking lots and I know it's really bad for you!! And she said "It's ok smoking doesn't harm you if you spit after you take every drag. The toxins from cigarettes go into your lungs and back out when you inhale/exhale. It's what's left and absorbed in your mouth that harms you." She lies a lot so I don't know if it's true I mean once she said she was going to come to the mall with me but told me she was ill but she was really with her boyfriend instead!!! Is this smoking thing true? I've had enough of her lies.