Tests were carried out in the Etruscan Tomb of the Triclinio in Cerveteri (Italy) to assess the effectiveness of different biocide products and their impact on microbic ecosystems in hypogea. The performance of four biocides (O. F. F., Fenticide 40, Metatin N-58-10/101, Previcur) was evaluated by cultural analyses of samples from different areas. Results showed that all products (except Previcur) are effective in controlling actinomycetes which were either totally eliminated or remarkably reduced for up to 6 months from the beginning of the treatment. Previcur was the only biocide found to be effective for the treatment of heterotrophic bacteria. 18 bibliographic references. Graph. Data tables.