A new recombinant protein called Antisecretory Factor (rAF) and homologues and peptide fragments thereof are described. The protein and the homologues and fragments thereof are useful for normalizing pathological fluid transport and/or inflammatory reactions in animals including humans. Antibodics against AF or homologues or fragments thereof are described. Nucleic acids coding for the protein or for homologues or fragments thereof are also described as well as vectors and hosts comprising the nucleic acids. The rAF and homologues and fragments thereof could be used for immunodetection, as feed additive for growing animals and as antidiarrheal and drugs against diseases involving edema, dehydration and/or inflammation.