The Most Prevalent Dangerous Drugs and Their Effects First: Heroin Derived from morphine found in the opium poppy plant.It causes short-term euphoria and severe lethargy. It may lead to respiratory arrest and death from overdose, and transmits diseases through shared needles. Effects: Respiratory depression, loss of consciousness, risk of infection (HIV, Hepatitis). Second: Cocaine Extracted from the leaves of the coca plant.It causes a temporary increase in energy and alertness, followed by a psychological crash. It can lead to fatal use due to clots or heart failure. Effects: Brain strokes, heart disorders, risk of sudden death. Third: Methamphetamine (Shabu) A powerful synthetic substance that causes severe agitation and mental disorders.Chronic use leads to tooth loss and brain damage. Effects: Hallucinations, aggressiveness, rapid health deterioration. Fourth: Fentanyl A very powerful synthetic opioid—much stronger than morphine—used medically but causes rapid death in small doses. Effects: Acute respiratory depression, loss of consciousness, rapid overdoses. Fifth: Cannabis and Drug Trafficking Cannabis is a plant-based substance used for smoking or eating.Although its effect is less compared to synthetic types, chronic addiction affects memory and concentration. Also, drug trafficking affects the entire society. Effects: Poor concentration, psychological disorders in some individuals, social and economic threat. Conclusion Prevention and awareness are the most important weapons in confronting the scourge of drugs.Addicts must be supported for treatment, awareness campaigns activated, and control over trafficking tightened. Al-Mustaqbal University, The First University in Iraq.