Described herein relates to methods and compositions for extracting hirudin from a plurality of leeches in vivo. The method may include contacting leeches with inducing membranes containing an inducing agent for a first predetermined time period. The inducing membranes may be removed from the leeches, and the leeches may be contacted with a regurgitation agent for a second predetermined time period in a container such that the leeches are induced to regurgitate regurgitation contents. The regurgitation contents may be collected and purified to obtain the hirudin.
