Accidental poisoning is frequent in domesticated animals. It may present no visible lesions, and it is therefore very important to recognise the symptoms which indicate the secret lesion. POISONING DUE TO FOOD. Under this title are included all forms of poisoning resulting from the ingestion of bad fodder. Such expressions as “intestinal typhus” and “typhic gastro-enteritis” only indicate a special stage in the condition, which is never twice the same. =Causation.= The most important changes in the food ingested do not consist in a mere modification in its chemical composition, but in the presence of various parasites which develop in grain and forage, after moistening, or after abnormal fermentation in the interior of the grains. These parasites are chiefly represented by fungi belonging to the genus Mucor: _Aspergillus_ or _Penicillium_; blight—_Puccinia graminis_, _Uredo linearis_; smut—_Tilletia caries_, _Ustilago segetum_, _Ustilago maydis_; yeasts of different kinds resulting from the fermentation of brewers’ grains; and, finally, unrecognised microbes which act by means of the poisons they secrete. =The symptoms= are always very vague. At first the only marked symptom is loss of appetite, accompanied by dryness of the mouth and muzzle, depression and constipation. The animals never clearly show signs of gastro-enteritis; nevertheless, the changes in general health point very clearly to a digestive origin. In cases of acute poisoning the symptoms develop rapidly. Torpor becomes more marked, the movements of the heart tumultuous, and the temperature rises to 105° Fahr. (40·5° C.), diminishing later until death occurs. In chronic forms of poisoning constipation is present at first, but is soon followed by profuse, fœtid, blackish diarrhœa, sometimes containing streaks of blood and accompanied by abdominal pain. In exceptional cases these digestive symptoms are amplified by the presence of broncho-pneumonia, pleuro-pneumonia, nephritis, and cystitis, as in poisoning by tannin and essential oils. These complications are of infectious origin. In young animals, like lambs and young pigs, still with their mothers alimentary intoxication may also occur though the mothers show no signs of illness. The passage of poisonous principles into the milk cannot be disputed. Moussu has seen numerous cases of alimentary intoxication in lambs whose dams were fed with decomposed beet pulp, and in sucking pigs whose mothers had received bad maize, turnips, etc. =Diagnosis.= Careful examination of the substances with which the animals are fed, and consideration of the history, prevent confusion with ordinary poisoning. Anthrax as a cause can easily be eliminated. =The prognosis= is grave, unless the practitioner is summoned early.