The problems are discussed regarding the published equation coefficients of Cheng and co-workers [J. Chem. Thermodynamics 98 (2016) 51-55] for mathematically describing the solubility behaviour of aloe-emodin in seven pure solvents using the Modified Apelblat equation and lambda h equation. The calculated solubility data using the published equation coefficients do not correctly describe the determined values as stated in the published paper. Larger differences are found between our back-calculated data and those reported in the authors' published paper. The curve-fit coefficients tabulated in Tables 2 and 3 are in error. (C) 2018 Elsevier Ltd.