Quantitative structure - activity relationships (QSARs) developed to evaluate percentage of inhibition of STa-stimulated (Escherichia coli) cGMP accumulation in T84 cells are calculated by the Monte Carlo method. This endpoint represents a measure of biological activity of a substance against diarrhea. Statistical quality of the developed models is quite good. The approach is tested using three random splits of data into the training and test sets. The statistical characteristics for three splits are the following: (1) n = 20, r(2) = 0.7208, q(2) = 0.6583, s = 16.9, F = 46 (training set); n = 11, r(2) = 0.8986, s = 14.6 (test set); (2) n = 19, r(2) = 0.6689, q(2) = 0.5683, s = 17.6, F = 34 (training set); n = 12, r(2) = 0.8998,s = 12.1 (test set); and (3) n = 20, r(2) = 0.7141, q(2) = 0.6525, s = 14.7, F = 45 (training set); n = 11, r(2) = 0.8858, s = 19.5 (test set). Based on the proposed here models hypothetical compounds which can be useful agents against diarrhea are suggested. (C) 2013 Elsevier Inc. All rights reserved.