The manufacture and control of oral solutions has presented some problems to the industry. While bioequivalence concerns are minimal (except for the antiseptic products such as phenytoin suspension), there are other issues which have led to recalls. These include microbiological, potency and stability problems. Additionally, because the population using these oral dosage forms includes newborns, pediatrics and geriatrics who may not be able to take oral solid dosage forms and may be compromised, defective dosage forms can pose a greater risk because of the population being dosed. Thus, this guide will review some of the significant potential problem areas and provide direction to the investigator when giving inspectional coverage.