In a preclinical study, ethyl propionate was infused intraduodenally for 3 hr in 32 male New Zealand rabbits.

Human cholesterol gallstones were put in separate glass test tubes, hepatic bile (2 ml) was added and gallstones were subsequently dissolved in 8 ml of either ethyl propionate or ethyl propionate/dimethyl sulphoxide (70/30). The in vivo situation was mimicked by creating turbulence manually using glass syringes (4-6 cycles a minute) and by exchanging solvents and bile every 15 minutes. Test tubes were incubated in the dark at 37 degrees Celsius. No cholesterol stone dissolved completely within the frame of 300 minutes, leaving a mean stone residue of 35% in ethyl propionate and 28% ethyl propionate/dimethyl sulphoxide mixture.