Serum of animal origin, like foetal calf serum (FCS), is used as a standard supplement for media to cultivate mammalian cells, mostly due to its growth-supporting properties. Unfortunately, animal serum has many disadvantages like the risk of contamination, high costs, fluctuations within the composition of different batches and the high amount of foetuses, which have to be harvested. To avoid all this, it is necessary to provide alternatives, which combine as many positive properties of the animal serum as possible but do not influence the cellular metabolism negatively. Today, several serum-free complete media as well as serum substitutes are commercially available. In the present study, a serum substitute, a serum-reduced medium and a serum-free medium were evaluated concerning their influence on the metabolism on the colon cancer cell line SW-480. The evaluation of morphological changes of the cells was done by microscopic analysis whereas differences in the volatile meta-bolome were analysed by solid phase micro extraction (SPME) followed by gas chromatography/mass spectrometry (GC/MS).