During development of a suitable formulation for a combination of Vitamin E and C for the above study, formulated tablets were found to darken during storage. Since the study was double blinded, it was necessary that the drug and placebo should physically remain unaltered. While further investigation revealed Vitamin C to be responsible for such color change, Vitamin E in combination with various grades of Vitamin C, i.e., pure crystals, 97.5% and 98.4% coated and 90% granulation were tried in order to provide best stable product. Tablets containing pure Vitamin C crystals were found most stable on subjective analysis. It was found difficult to quantitate the color change instrumentally. To circumvent the problem, tablet formulations containing only Vitamin C (without Vitamin E) were formulated and stored under different conditions of temperature and moisture. The quantitative estimation of color change during storage is underway.