The concept of septic shock represents a significant challenge in the medical field, as it involves an out-of-control immune reaction to a systemic infection. This serious condition results from the complex interaction of multiple factors that develop in sequence. The starting point is an infection, often of bacterial, viral or fungal origin, that begins locally and spreads rapidly throughout the body. This spread occurs through the circulatory and lymphatic systems, causing the pathogenic microorganisms to reach different parts of the body. The sources of infection can vary, including infections of the respiratory tract, urinary tract, gastrointestinal tract and surgical wounds. Infection triggers an immune response, which is usually vital for fighting pathogens, however, in some circumstances, this immune response can become excessive and incorrect. A 'cytokine storm', a generalised inflammatory reaction, occurs, where cytokines, chemical messengers of the immune system, are overproduced. This over-production of cytokines causes large-scale inflammation, leading to tissue and blood vessel damage. A crucial element in this process is the endothelium, the inner lining of blood vessels. Inflammation and a storm of cytokines cause dysfunction of this tissue resulting in vasodilatation and collapse of the patient's blood pressure with all the associated damage. In parallel, there is an increase in the production of free radicals, highly reactive molecules that can damage cells. This situation further contributes to inflammation and tissue damage, creating a vicious circle. The interaction of these mechanisms can lead to organ failure, due to accumulated damage to the heart, lungs, liver and kidneys. Multi-organ failure is a critical phase of septic shock, requiring intensive and timely medical treatment.