Analysis of pyracetam in available parent powders using differential scanning calorimetry (DSC) showed that there are at least two main polymorphic forms of pyracetam on the pharmaceutical market. One of these is converted into the other during heating and storage. Two polymorphic forms of pyracetam have been found in pyracetam capsules, in contrast to tablets where only one form is present. The results show that amorphization of crystalline active ingredient during heating of dosed forms including polyethyleneglycol or other carriers should be taken into account during analysis by means of DSC.