Twenty-two patients with chronic pulmonary disease were treated with three different expectorants for one week. Group A, consisted of 9 cases, received 100 ch, u. daily of α-Chmotrypsin buccule, administered in the oral cavity; Group B, comparised of 7 cases, received 24mg daily of Bromhexine hydrochloride, administered orally; Group C, comprised of 6 cases, received 30mg daily of Serratiopeptidase, also administered orally. The effects of the expectorants on sputum viscoelasticity in vivo were studied over frequencies from 10^-3 to 10° rad·sec^-1 using the Raised Cosine Pulse method. Results were as follows:
1) The symptoms of expectoration and/or coughing improved in about half of the cases in each group, and the differences among the groups were not pronounced.
2) In Group B, the absolute values of G′ (storage modulus) and G′′ (loss modulus) in 5 cases (71%) decreased over all studied frequencies after the treatment. On the other hand, no clear change, as a group, was found in the absolute values of G′ and G″ from the cases in Group A and C.
3) The peak of G″, which indicated a relaxation region, became more distinct after treatment than before in 7 cases (78%) of Group A and 3 cases (50%) of Group C. On the other hand, in Group B, this change of the peak of G″ was seen in only one case (17%). Moreover, the incidence of the change of the peak of G″ in Group A was significantly different from that in Group B (p<0.01, Chi-square test).