pathogenic

This is a clinical and scientific term used to describe the ability of an agent to create illness. It carries a neutral, objective tone in medical contexts but implies danger or toxicity when discussed in public health scenarios. Unlike 'infectious' (which describes how a disease spreads) or 'virulent' (which describes the severity of the damage), 'pathogenic' focuses specifically on the capacity to initiate the disease process itself. It is most commonly used in laboratory reports, epidemiological studies, and medical literature. In casual conversation, people usually prefer simpler terms like 'harmful' or 'disease-causing'.