There are discordant guides and protocols when it comes to treating a patient who has ingested a caustic substance. Different ideas or tendencies speak in favour of dilution, neutralization, provoking vomiting, carrying out stomach washes, etc., depending on the milieu where the problem arises: at home, at the health centre, emergency service or hospital. The same occurs with the type of diluent or neutralizing agent to be used, how and when to start the treatment pattern with corticoids and/or antibiotics and antisecretory, if indeed this is necessary. We have carried out an exhaustive bibliographical study, an experimental work and a study of the different diagnosis and treatment guides and protocols used in different Spanish hospitals. At the experimental level it was found that there are histopathological markers that advise against the use of diluent substances following the ingestion of caustic alkali. Except in the cases of ingestion of solid caustic substances -crystalline or granulated- categorical contraindications are given against dilution. Corticoids are not efficient when a caustic acid is ingested; their use is more than questionable following the ingestion of caustic alkali. Diagnosis and quality of treatment are based on endoscopy. There is no single criterion that defines which moment (the time following ingestion) is the most convenient for carrying this out, although the period between the first 6-12 hours is the most suitable. We present an independent protocol of diagnosis and treatment -in the form of algorithms- that must be followed after the ingestion of caustic acids or caustic alkali.