What illness is listed as the cause of Mendeleev's death?

What illness is listed as the cause of Mendeleev's death? Influenza.

Dmitri Mendeleev died in Saint Petersburg on 2 February 1907, aged 72, and biographies commonly record influenza as the cause of death. His final years followed decades of international recognition for organizing the periodic table and predicting elements that had not yet been discovered.

Influenza is often confused with pneumonia in historical death records because influenza can cause serious respiratory complications, including viral or secondary bacterial pneumonia. However, the standard biographical account identifies influenza itself, not cholera, tuberculosis, or pneumonia, as Mendeleev's listed cause of death.

Mendeleev's death came more than three decades after his 1869 periodic-table publication. By then, discoveries such as gallium and germanium had strongly supported his predictions about gaps in the table. He was buried at Literatorskie Mostki in Saint Petersburg.