Unconventional treatment of diabetes with starch from unripe fruits of lobeira is a practice very common among Brazilian people. We have investigated the effects of starch on tissues glycogen content and some serum biochemical parameters of rats receiving the drug diluted in water. Twenty male Wistar rats were divided in controls which received water, diabetic controls, diabetic starch-treated group and starch-treated control group which received 5 g/Kg body weight of lobeira starch in water. After 30 days of treatment, the animals were sacrificed. Liver, brain and heart glycogen content, as well as serum glucose, triglycerides and cholesterol were determined. The results for starch-treated control group were: hepatic glycogen 1,9 ± 0,4 mg/g; brain glycogen 0,13 ± 0,05 mg/g; heart glycogen 0,10 ± 0,02 mg/g; glucose 130 ±  28 mg/dL; cholesterol 75 ± 1,8 mg/dL; triglycerides 57 ±  6,4 mg/dL. The results for diabetic controls were: hepatic glycogen 2,7 ± 0,8 mg/g; brain glycogen 0,15 ± 0,09 mg/g; heart glycogen 0,25 ± 0,06 mg/g; glucose 184 ± 10 mg/dL; cholesterol 69 ± 11 mg/dL; triglycerides 44 ± 11 mg/dL. The results for diabetic starch-treated group were: hepatic glycogen 1,6 ± 0,3 mg/g; brain glycogen 0,13 ± 0,04 mg/g; heart glycogen 0,20 ± 0,04 mg/g; glucose 414 ±  113 mg/dL; cholesterol 88 ± 22 mg/dL; triglycerides 92 ± 45 mg/dL. Serum biochemical parameters were not significantly modified by starch feeding.  Treatment with lobeira starch has no effect on lipid and carbohydrate metabolism.  Glycogen content of insulin dependent tissues (liver and heart) and insulin-independent tissues (brain) were not modified compared to the controls. As the performed assays serve as marker for insulinomimetic activity, these results suggest that starch from Solanum lycocarpum has no effect on glucose influx and glycogen storage.