An impurity in a drug is any chemical component that has no chemical entity defined as a drug substance, they remain with the active pharmaceutical ingredients (APIs), or develop during formulation, or upon aging. The safety of a drug depends upon the toxicological properties of the active substance and its pharmaceutical impurities. Temperature, humidity and pH play an important role in degradation processes. Paracetamol is hydrolyzed to paminophenol and acetic acid. p-chloroacetanilide could be one of the most related substances to paracetamol. Aspirin undergoes hydrolysis to give salicylic acid and acetic acid. Since paracetamol and aspirin are of the most used drugs among different age groups, they were chosen to be assayed in pharmaceutical products in the Gaza Strip. A descriptive study was chosen to examine drug related data. The samples were selected from the north and the south governorates of the Gaza strip. Three pharmacy groups of each area were selected, UNRWA, MOH and private pharmacies. According to sample size, 150 tablets, 40 suppositories and 10 syrups of paracetamol produced by different companies were randomly selected. For aspirin,138 tablets produced by different companies were randomly selected. Paracetamol and aspirin products were assayed quantitatively by spectrophotometry and detected for impurities by TLC. The results were analyzed using SPSS. Statistically significance is considered when P-value was less than 0.05. Different TLC systems were examined to modify the test on impurities. Aspirin content ranged from 82-103%, 52% of examined aspirin tablets did not meet the pharmacopoeial requirements. TLC examination of rejected samples showed detectable salicylic acid spots. No statistical significance was established between aspirin content and shelf-life. A remarkable variation among aspirin manufacturers was established. Aspirin and salicylic acid were quantified in the samples using spectroscopy without pre-separation. ë max of aspirin and salicylic acid were 275 and 303 nm in ethanol and glacial acetic acid (98 : 2), respectively. Paracetamol content ranged from 92-97%. All the examined dosage forms met the pharmacopoeial criteria. No impurities were detected in the tested paracetamol products. The statistical tests showed no significance between paracetamol content and shelf life also no variation among manufacturers. Detection of impurities were effectively performed by thin layer chromatography on silica gel plates using [Ethyl acetate: Acetic acid 200: 1 V/V] and [Toluene: Acetone: Acetic acid 20ml: 20ml: 20 drops] as mobile phases for aspirin and paracetamol, respectively. Potassium dichromate solution 0.5% was used effectively to detect 0.005% para-aminophenol solution which represent the tolerance limit of pharmacopoeia. As a conclusion, aspirin tablets in the Gaza Strip show variation in their active ingredient contents. Salicylic acid was detected in many randomly selected samples. Paracetamol products were free of impurities and met the pharmacopoeial requirements.