[Correct use of Spanish when writing biological papers].

We present a list of the most frequent errors in biological manuscripts written in Spanish, and we explain which are the recommended options. Our article is based on the International Codes of Nomenclature, and the guidelines of the Real Academia de la Lengua and the Council of Science Editors. We group the indications in four categories: lexical errors (e.g., English cognates); spelling (graphic accents, punctuation, font), morphology (use of prepositions) and style (linguistic economy).