Cigarette smoking is commonly recognized for its carcinogenic effects. Clinical studies have found that smoking also increases the risk of stress fracture and decreases the fusion rate during bone healing. Nicotine is the most well-known chemical found in cigarettes, and has been implicated in the debilitating effects of smoking. This study investigated the effect of nicotine and secondhand smoke on the fracture resistance of cortical bone taken from rabbit tibias. Nicotine was delivered via a transdermal nicotine patch and a smoking chamber. There were three groups in this study: the control group, a 5-week nicotine patch group, and a 5-week smoking group. The results of this study showed that rabbits exposed to secondhand smoke for 5 weeks had a significant reduction in cortical bone fracture toughness compared to control rabbits, while the fracture toughness of rabbits exposed to nicotine alone was not significantly different than the fracture toughness of the control group.