The results of two acute treatment tests using SMS 201-995 (SMS), over a 24 hour period in acromegalic patients are presented. Test number 1: Seventeen cases with a mean age of 44.3 +/- 11.9 (21/71) years with an evolution of 9.2 +/- 6.5 (2/20) years and GH of 30.1 +/- 21.1 (5.2/96.4) ng/ml were treated with 50 micrograms/8 hours (8, 16, and 24 hours) of subcutaneous SMS. Test number 2: 26 cases with a mean age of 45.5 +/- 15.5 (21/71) years with an evolution of 9.1 +/- 7.9 (2/35) years and GH of 28.6 +/- 22.2 (5.2/96.4) ng/ml were treated with 100 micrograms/8 hours (8, 16, and 24 hours) of subcutaneous SMS. Ten point GH profile in 24 hours is evaluated in both tests and in number 2 insulin and blood sugar levels are measured at the same time points. In both tests GH is significantly reduced being the 100 micrograms/8 hour treatment schedule more efficient. The results in the decrease of GH in test number two are related to those obtained using SMS in prolonged treatments. Inspire of the reducing effect that SMS has on insulin levels, its influence on the blood sugar profile is scare.