Systemic administration refers to the delivery of a substance, such as a drug or a therapeutic agent, throughout the entire body via the bloodstream. This method of administration allows for the substance to reach various tissues and organs in the body, where it can exert its effects. Systemic administration can be achieved through various routes, including intravenous, intramuscular, subcutaneous, and oral administration. This approach is commonly used in medical treatments to ensure widespread distribution of the substance and to target multiple areas of the body simultaneously.