Background: Many older patients have difficulty in swallowing their tablets and capsules. Dose form modification, by crushing tablets or opening capsules, is often used by nurses to administer such medication. Methods: Electronic searches of five literature databases on tablet crushing and capsule opening were carried out. A review of medication incident reports involving tablet crushing from the U.K. National Reporting and Learning System (NRLS) was also undertaken. An observational study of medication administration on two long-stay wards for older mentally ill inpatients was carried out in a large psychiatric hospital. Results: Only 17 incidents involving tablet crushing were reported to NRLS in 13 months. In the observational study, the administration of 1257 oral doses of medication at 36 medication rounds was observed. Tablets were crushed or capsules opened for 25.5% (266/1045) of solid oral doses. For 44.0% (117/266) of these doses the tablet crushing had not been authorized by the prescriber. For 4.5% (12/266) of doses crushing was specifically contra-indicated by the manufacturer. In 57.5% (153/266) of doses, tablet crushing was avoidable by the correct use of more suitable preparations. Crushing caused contamination, spillage and hygiene problems. Conclusions: Although tablet crushing and capsule opening are common practices, they are rarely reported as causing patient harm. Tablet crushing can often be avoided by the use of more suitable preparations. Crushing tablets and opening capsules are contra-indicated for some preparations. Older patients' medication may benefit from review by a pharmacist in order to optimize safe medication administration. Where tablet crushing is unavoidable, attention to cleanliness, contamination and spillage are necessary.