The paper discusses issues that research, in both the world and the Czech Republic, has for the most part been resolved. Yet in practice very little attention has been paid to them in this country. And yet non-specific microbial toxicoses produced by the enzymatic activity of various microorganisms in certain substrates, more specifically in food, may cause not only fairly insignificant, but also highly significant threats to human health, in both individuals and large groups of the population. They are thus important not only from a microbiological, but also epidemiological point of view. In this respect the greatest danger represent microbes with a lipolytic or proteolytic activity. Aldehydes, ketones, peroxides, epoxides and various other polymeres may be generated in fats, more particularly in butter, and in foodstuffs containing small or large proportion of fats, while various forms of biogenic amines may be found in foodstuffs containing proteins. The result are non-specific toxicoses - epidemiological examinations clearly point to an alimentary toxicosis, yet bacterial toxins cannot be demonstrated and possible products of enzymatic microbial activity are disregarded. In all such instances we should not only explore the suspicious foodstuffs for the presence of pathogenic or conditionally pathogenic microbes and bacterial toxins, but we should also carry out qualitative and quantitative investigations to detect lipolytic or proteolytic microorganisms (depending on the content of the foodstuff) and their metabolic activity.