Biological target interaction is a process by which drugs or other chemicals interact with cellular targets to produce an effect. This can occur through direct binding, enzyme inhibition, receptor activation, or any combination of these mechanisms. In the field of pharmacology, drug development and pharmaceutical research, understanding how drugs bind to their biological targets is an integral part of designing effective and safe medical treatments.

The main types of biological target interactions are direct binding and enzymatic inhibition. Direct binding occurs when the drug binds directly to its intended target molecule in order to affect its function. For example, immunosuppressant drugs used in transplant rejection prevention will bind directly to certain receptors on immune cells in order to inhibit their activity. Enzyme inhibition involves preventing the action of specific enzymes that normally catalyze biochemical reactions within cells; this can be done by competing for active sites on enzymes or blocking substrate access into active sites altogether. Drugs designed for treatment of heart disease often act as enzyme inhibitors in order to reduce cholesterol levels in blood vessels.