The document discusses various routes of drug administration in laboratory animals. It describes enteral routes including oral, intragastric gavage, and rectal administration. It also discusses various parenteral routes such as intravenous, intramuscular, subcutaneous, intraperitoneal, and intradermal injection. For each route, it provides details on the procedure, optimal injection sites and volumes for rats and mice. Common laboratory animals used include rats, mice, rabbits, guinea pigs, cats, dogs and monkeys.