Full agonists are substances that bind to specific receptors in the body and activate them to produce a maximum biological response. They mimic the action of natural substances, such as neurotransmitters or hormones, and can lead to significant physiological effects. For example, morphine is a full agonist at the mu-opioid receptor, providing strong pain relief. In contrast to partial agonists, which activate receptors but produce a weaker response, full agonists fully stimulate the receptor's activity. This characteristic makes them effective in various medical treatments, including pain management and anesthesia. However, their potency can also lead to side effects and potential for addiction.