A performance analysis of indirect natural convection solar dryer (INCSD) was carried out by drying anti-diabetic medicinal products like coccinia grandis, allium cepa, and emblica officinalis by cutting into different orientations. Drying results shows that thickness, orientation of cut, and surface area plays a vital role in the drying characteristics of the products in INCSD. The average collector and dryer efficiency of INCSD was 15% and 7%, respectively. Drying time was reduced up to 11 hr in INCSD than open sun drying. Alpha amylase inhibition assay values for products dried under open sun (15.67%, 5.89%, and 8.56%) showed better results, whereas minerals like potassium content in allium cepa (597 mg/100 g), sodium content in coccinia grandis (130.1 mg/100 g), magnesium content in allium cepa, and emblica officinalis (80 mg/100 g) were higher when dried in INCSD. Vitamin C and sugar content in products were almost same for both INCSD and open sun drying. Practical applications Indirect natural convection solar dryers are mainly benefited by small-scale farmers as it takes less drying time and possess better quality when compared to open sun drying. Drying anti-diabetic medicinal products in INCSD can be considered as a boon for pharmaceutical industries as the dryer can give good-quality dried products that can be used for preparing anti-diabetic medicines. It can also reduce the production cost of anti-diabetic medicines. © 2019 Wiley Periodicals, Inc.