Mouse intestinal secretions can be readily obtained without harm to the mice by administering a lavage solution to them intragastrically followed by pilocarpine intraperitoneally. These secretions are rich in proteases but this enzyme activity can be blocked by addition of a mixture of inhibitors. Both total and specific IgA antibody could be measured in these secretions using ELISA techniques. The total IgA recovered was found to vary considerably, even in the same group of mice sampled on multiple occasions. Specific IgA anti-cholera toxin antibody was easily demonstrable in the intestinal secretions of mice fed cholera toxin but not of mice fed an irrelevant antigen. Expression of the specific IgA antibody per unit of total IgA recovered is desirable in order to correct for the variable recovery of IgA. © 1984.