The digestion of human and rodent blood by Aedes aegypti (L.) was investigated by immunoblot analysis, using polyclonal antisera produced against serum proteins. Rates and patterns of digestion of the principal proteins in serum (albumin and immunoglobulin G) appeared to differ depending on the source of blood. Overall, most intact proteins disappeared 24-48 h after blood ingestion by Ae. aegypti, and albumin and immunoglobulin G appeared to be the most persistent proteins, irrespective of the source of blood.