Introduction In the pharmaceutical area, investigation of physical interaction which is very possible to occur along the mixing manufacturing process of dosage forms is an important issue because a lot of physical properties of drugs especially in solid state dosage forms could be inuenced. Such changes as stability, drug performance, dissolution prole, pharmacokinetics prole, and, moreover, the pharmacological eect should be much impacted by the interactions [1-3]. Physical interactions in the solid state dosage form frequently occur even in storage and distribution time of dosage forms [4, 5]. erefore, the simple technique to detect the interaction might be very useful. Along last decades, Koer’s hot stage contact method, which observed the co-recrystallization from 2 compounds from their hot molten state, has been used as a simple method to detect the cocrystal formation as an indicator for physical interaction occurrence . Unfortunately, in pharmaceutical area, there are a lot of thermolabile compounds which cannot be crystallized after melting, because we have arranged a simple method used to detect physical interaction of the thermolabile compounds. is method was conducted by observing the process of cocrystallization and its behavior on crystallization contact area of 2 drugs from their solution under microscope polarization and melting point determination. Briey, this method is developed from Koer’s contact methods by changing the comelting technique to the cosolvating crystallization. Recently, we have investigated the cold contact suitability to detect and identify the physical interaction of 3 drug combinations which are usually found in the dosage forms. Acetaminophen-pseudoephedrine HCl is found in antiinuenza dosage forms, methampyrone-phenylbutazon in analgesic dosage forms, while amoxicillin-clavulanate in antibiotic combination dosage forms. All of these combinations have brought some troubles in mixing and compounding which caused high variability on their dosage forms quality. We used the cold contact method to detect the possibility of physical interaction of these drug combinations and evaluated the method by dierential scanning calorimeter (DSC) as a primary thermal analysis method.