Clinicians have had concerns about particulate matter contamination of injectable drug products since the development of the earliest intravenous therapeutics. All parenteral products contain particulate matter, and particulate matter contamination still has the potential to cause harm to patients. With tens of millions of doses of injectable drug products administered in the United States each year, it is critical to understand the types and sources of particulate matter that contaminate injectable drug products, the possible effects of injected particulate matter on patients, and the current state of regulations and standards related to particulate matter in injectable drug products. Today, the goal of manufacturers, regulators, and standards-setting organizations should be to continue to minimize the risk of particle-induced sequelae, especially in high-risk patients, without trading unnecessary manufacturing burden for minimal safety gains.