Concentrations of acid-soluble L-carnitine and inositol were determined in heart, kidney, muscle, pancreas, liver, brain and blood of genetically diabetic obese db/db and their nondiabetic control C57BL/6J (CBL) mice. Results were compared to a group of diabetic and CBL mice fed ethanol (ETOH) 4 g/kg daily for 58-64 days. In CBL and db/db mice, heart muscle was found to have the greatest and brain the least content of carnitine. Diabetes caused a significant decrease in hepatic concentration of carnitine but did not affect carnitine concentration of heart, kidney, skeletal muscle, brain and pancreas. ETOH intake had no effect on carnitine content of any of the tissues studied. Free inositol content was highest in brain and lowest in skeletal muscle of CBL and db/db mice; diabetes or ETOH intake did not affect tissue inositol content. Except for liver, neither diabetes nor ETOH intake affects tissue carnitine or inositol concentration.