Serotonin syndrome is a potentially life-threatening condition resulting from excessive serotonin levels in the brain, often due to medication interactions or overdose. Although it is often searched online and considered rare in clinical practice, recognizing its symptoms and knowing why it requires urgent attention can save lives. The Hunter Criteria is the widely accepted tool for diagnosing serotonin syndrome. It focuses on the presence of clonus (involuntary muscle contractions), agitation, diaphoresis (excessive sweating), hyperreflexia (overactive reflexes), tremor, and elevated body temperature. Patients on serotonergic medications, such as selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), certain cough suppressants like dextromethorphan (found in products like Robitussin Maximum Strength), and drugs like fentanyl and ondansetron, are at risk. Notably, recreational substances such as LSD, MDMA (Molly), cocaine, and amphetamines can also raise serotonin levels, increasing the risk of this syndrome. Common symptoms include muscle rigidity, confusion, restlessness, heart palpitations, dizziness, and inability to relax properly. It is crucial for both healthcare providers and patients to be aware of the potential for serotonin syndrome, especially when multiple serotonergic agents are combined. Early identification and medical intervention, including discontinuing offending medications and supportive care, are vital to prevent severe complications. In summary, while serotonin syndrome is rare, understanding the contributing medications and recognizing signs like clonus, agitation, and hyperreflexia through the Hunter Criteria can aid timely diagnosis. Staying informed on the risks associated with both prescribed drugs and certain recreational substances helps ensure better outcomes and patient safety.