<s>[INST] hi,I have smoked poppers for about 2 years now.A popper is when you take a little rip of tobacco about 1-2 cm and put it in a metal shaft and put a bit of weed on top and smoke it through a water bong. I also smoke maybe 5 cigarettes a day.  for the last 2 years ive been doing this and sometimes i cough up some dark brown in my phlegm, I am just curious how bad this is effecting my lungs as it is unfiltered tobacco that i am smoking, the water barely filters,  am i at big risk of getting lung cancer after 2 years ? [/INST] Hello and welcome to Chat Doctor, Smoking tobacco in any form is a risk factor for developing lung cancer. Not only lung cancer, tobacco is known to cause cancer of many other organs like bladder, pancreas, kidney, head and neck region, aer-digestive tract. Since, you are coughing up dark brown colored phlegm (probably blood tinged sputum) the possibility of lung cancer increases. Tobacco is the worst known carcinogen (cancer causing agent). Long duration of smoking tobacco increases the risk of developing cancer, but it can develop after short interval of 2 years also if the usage is very high. Usage of tobacco should be discontinued. There are many rehabilitation centers and Chat Doctor. Thanks and take care </s>