Study of mechanisms of cellular and humoral immunity of larvae of the blowworm Calliphora vicina has revealed three groups of pharmacologically active substances perspective for use in medicine--alloferons, allostatins, and antimicrobial peptides. Alloferons--the family of peptides of C. vicina stimulating selectively the cytotoxic activity of natural killers of the evolutionary ancient group of immunocompetent cells playing the key role in the system of mammalian antiviral and antitumor immunity. Alloferons are used in medicine for treatment of herpes-viral infections and viral hepatitis B. Allostatins-synthetic peptides combining structural characteristics of alloferons and some mammalian immunologically active proteins. Allostatins, like alloferons, produce stimulating effects on cytotoxic activity of natural killers and interferon production, but differ from them by pronounced adjuvant properties--the ability to enhance immune recognition of alien antigens. At present, allostatins are used to increase resistance of skin and mucosae to viral infections; in future, they might also find use in immunotherapy of cancer and other diseases. Another protein and peptide group perspective for use in medicine serve as antimicrobial peptides in immune response of larvae C. vicina. The study of the agent containing defensins, cecropins, diptericins, and praline-enriched C. vicina peptides shows the drugs of this type to be of great interest as the tool for treatment and prevention of infections caused by antibiotic-resistant bacteria.