Acetylsalicylic acid, paracetamol, and ascorbic acid which are used for the pain reliever and fever reducer were analyzed without any prior reservation by means of spectrophotometry-chemometry. The experimental calibration matrix was designed by measuring the absorbance within the range of 200-400 nm for 19 samples of acetylsalicylic acid, paracetamol, and ascorbic acid. Absorbance and concentration values were analyzed using Minitab and other chemometric programs to calculate estimated concentrations by PCR and PLSR. In the first step the synthetic mixtures including acetylsalicylic acid, paracetamol, and ascorbic acid were prepared and absorbance values were obtained according to spectrophotometry. In the second step, amounts of acetylsalicylic acid, paracetamol, and ascorbic acid were calculated in effervescent tablet (Afebryl (R)). Standard deviations were accomplished. This study encouraged us to apply the developed methods for drug analysis. The methods presented in this paper are rapid and do not need any separation process or preliminary treatments for the analysis.