The development of sustainable animal production systems based on pastures requires the knowledge of animal and vegetation responses to the different management strategies. The study of pasture x animal interaction needs the development of appropriate methodologies to obtain information about intake, digestibility and composition of the diet selected by grazing animals. During the last few years the n‑alkane technique has been developed and it gives numerous possibilities for research in grazing ecology. This review describes this technique: its methodology, development, possibilities and limitations.