Synthetic fentanyl adulteration has become a significant threat to public safety. It is commonly mixed into other drugs of abuse to lower costs and increase its addictive potential. Diffuse alveolar hemorrhage (DAH) is a rare but life-threatening complication associated with the use of fentanyl-laced products. Given the current trend, we anticipate an increase in the incidence of DAH. It is crucial to recognize and treat DAH early in its course for better outcomes. We present a case of DAH due to an overdose of marijuana laced with fentanyl, manifesting as hemoptysis, and provide a review of the current literature on the topic.