A detection device for detecting volatile organic compounds in faecal gases, which device is suitable for screening of colorectal cancer and/or colorectal adenoma and comprises: - a reception seat for a faeces sample; - a plurality of semiconductor sensors or transducers, each configured for detecting one or more respective volatile organic compounds of faecal gases and each of chemoresistive type; - an outer casing which houses internally said sensors or transducers, said outer casing comprising a plurality of chambers, each housing a respective sensor or transducer or group of sensors or transducers; - feeding means for supplying a flow of air on the faeces sample and to said sensors or transducers, wherein said feeding means of a flow of air comprises: ▪ a pump configured to draw a flow of ambient air; ▪ a pneumatic circuit connected to said pump and configured to supply said flow of ambient air, in series, on the faeces sample and to said plurality of chambers; ▪ means for adjusting and/or interdicting the flow of ambient air (45, 46, 47, 48), arranged on said pneumatic circuit and configured in such a way as to allow a selective feeding of the air flow through the faeces sample and/or to said sensors or transducers; ▪ bypass means (412, 46) of the faeces sample, that can be activated to supply the flow of ambient air only to said sensors or transducers; and - a processing unit, in communication with said sensors or transducers and configured to provide an output datum on the presence of colorectal cancer and/or colorectal adenoma, wherein the arrangement is such that said chambers, and then the sensors or transducers housed therein, are traversed in series by said flow of ambient air, and wherein the feeding means is configured to provide a laminar flow of ambient air to the sensors or transducers. - a reception seat for a faeces sample; - a plurality of semiconductor sensors or transducers, each configured for detecting one or more respective volatile organic compounds of faecal gases and each of chemoresistive type; - an outer casing which houses internally said sensors or transducers, said outer casing comprising a plurality of chambers, each housing a respective sensor or transducer or group of sensors or transducers; - feeding means for supplying a flow of air on the faeces sample and to said sensors or transducers, wherein said feeding means of a flow of air comprises: ▪ a pump configured to draw a flow of ambient air; ▪ a pneumatic circuit connected to said pump and configured to supply said flow of ambient air, in series, on the faeces sample and to said plurality of chambers; ▪ means for adjusting and/or interdicting the flow of ambient air (45, 46, 47, 48), arranged on said pneumatic circuit and configured in such a way as to allow a selective feeding of the air flow through the faeces sample and/or to said sensors or transducers; ▪ bypass means (412, 46) of the faeces sample, that can be activated to supply the flow of ambient air only to said sensors or transducers; and ▪ a pump configured to draw a flow of ambient air; ▪ a pneumatic circuit connected to said pump and configured to supply said flow of ambient air, in series, on the faeces sample and to said plurality of chambers; ▪ means for adjusting and/or interdicting the flow of ambient air (45, 46, 47, 48), arranged on said pneumatic circuit and configured in such a way as to allow a selective feeding of the air flow through the faeces sample and/or to said sensors or transducers; ▪ bypass means (412, 46) of the faeces sample, that can be activated to supply the flow of ambient air only to said sensors or transducers; and - a processing unit, in communication with said sensors or transducers and configured to provide an output datum on the presence of colorectal cancer and/or colorectal adenoma, wherein the arrangement is such that said chambers, and then the sensors or transducers housed therein, are traversed in series by said flow of ambient air, and