Although English has been the lingua franca of science for over a century, young researchers often find it difficult to produce a manuscript for an international journal in a style acceptable for publication.  This short course, which requires a good knowledge of English, is dedicated to the technique of scientific writing, in particular in the medical and biological fields. The common grammatical errors of morphology and syntax often encountered at editing are highlighted. Specific areas include use of pronouns, punctuation and dangling participles, as well as abbreviations, units of measure, and choice of standard scientific terms. The different types of scientific publications and the logical sequence of presentation of the work done in the sections of the article are also described. Examples of text editing are used to deal with finer points of style, such as how to organize the text in paragraphs, and how to avoid redundancy, elegant variation, or ambiguous phrasing.