Intraperitoneal injections in rodents are commonly used for what purpose?

• A. Euthanasia
• B. General anesthesia only
• C. Oral administration
• D. Topical application

Answer: (A)

Intraperitoneal delivery uses the peritoneal cavity to introduce a solution, which then rapidly enters the systemic circulation through the rich blood supply there. In small rodents, this allows a euthanasia agent to reach the brain quickly, producing rapid loss of consciousness and death. This route is practical and commonly used because it is easier to perform reliably in mice and rats than intravenous injections, which can be technically challenging due to tiny veins. While intraperitoneal injections can be used to deliver anesthesia or analgesia in some protocols, their primary association in lab settings is with euthanasia. They are not used for oral administration or topical application, which involve completely different routes.