PURPOSE: To obtain a sputum preserving liquid which does not require an operation for separating a viscous liquid component by strong shaking and mechanical stirring in the stage of inspection by incorporating 2,3-dihydroxy-1,4-dithiol butane as a sputum dissolving agent into the sputum preserving liquid.
CONSTITUTION: The 2,3-dihydroxy-1,4-dithiol butane is incorporated into the sputum preserving liquid. The preferable compsn. of the sputum preserving liquid is 0.005W0.1wt% 2,3-dihydroxy-1,4-dithiol butane, 40W60wt% ethyl alcohol, 1W5wt% PE glycol, 0.01W0.1wt% antioxidant and the balance water. The need for making various operations to avert the adverse influence of the viscous liquid is thereby eliminated in the case of making the diagnosis of the sputum cells. The quick and efficient inspection is thus made possible.