In patients hospitalized in intensive care units (ICUs) nasogastric tubes are used for enteral feeding and solid pharmaceutical preparations are commonly administered. These drugs must be crushed before administration, which may alter their pharmacokinetic properties and consequently their therapeutic effects and adverse reactions, etc. The aim of this study was to review the orally-administered drugs used in our unit that should not be crushed, to propose alternative measures and to make recommendations for their correct administration. Their descriptive study was performed in the ICU of a University Hospital with 12 general-purpose beds. We reviewed all the oral medication currently administered in our unit and its form of administration through the nasogastric tube. Oral pharmaceutical preparations that should not be crushed were identified through a review of articles in MEDLINE published between 1991 and 2000 and through consultations with various pharmacy departments. Alternatives to these drugs were sought. Of the 115 drugs used in our unit, 50 could not be crushed. The pharmaceutical preparation of this group of drugs should not be modified because crushing would alter their characteristics, pharmacokinetic properties, etc. We present alternatives and make recommendations for their correct administration. In conclusion, a practical guide for the administration of drugs through nasogastric tubes is required. In our unit, such a guide would increase the efficacy and safety of the pharmacological treatment administered in this way. Collaboration with the pharmacy department is also advisable.