Émile Küss (1 February 1815 – 1 March 1871) was a French physician who, with Charles-Emmanuel Sédillot, performed the first recorded biopsy on a tumour.

[6] Émile Küss and Charles-Emmanuel Sédillot were amongst the few who believed that cancer cells could be recognised by how they looked under the microscope, as described by Adolph Hannover in 1843.

[1] They published their research on microscopic diagnosis in Recherches sur le cancer in 1846 and by 1847 they were performing punch biopsies of tumours using a specially designed instrument, as described by Küss:[1] On plunging this instrument into a tumor to any depth, we can extract a minute portion of the tissue of which its various layers are composed.

In this manner a microscopic examination of the tumor can be practiced on the living subject, and its nature ascertained before having recourse to an operation.

[3] He re-entered politics in 1869 to campaign for Charles Boersch who later became prefect of Strasbourg while he was mayor, and in 1870 he argued against Napoleon III's plebiscite.