Because of the tumors in her lungs, Hazel can’t breathe very well and relies on an oxygen tank connected directly to her nose by a set of tubes called a cannula. Throughout the novel, Hazel refers to the difficulty of carrying it up and down stairs, or in and out of cars. It constantly gets in the way and hampers her motion, and it also marks her as “different,” causing people to treat her with embarrassment or extra caution. The tank symbolizes the burden cancer has placed on her, that she has to carry throughout life, and she takes it off only rarely, in special moments, like when she and Augustus have sex or when she bids him goodbye in his casket. 

When Hazel first talks to Augustus outside the Support Group, she is shocked to see him pull out a cigarette and toy with it, until he explains that it’s a metaphor for looking at Death up close but—by not lighting the cigarette—not giving it the power to harm him. The cigarette symbolizes Augustus’s courageous, even defiant attitude toward his illness: he can’t escape death; it will never be far from him, but he refuses to “give in” to depression or powerlessness.