An increasing number of newly discovered drugs are poorly water-soluble and the use of natural and synthetic lipids to improve the oral bioavailability of these drugs by utilizing the digestion pathway in-vivo has proved an effective formulation strategy. The mechanisms responsible for lipid digestion and drug solubilisation during gastrointestinal transit have been explored in detail, but the implications of drug precipitation beyond the potential adverse effect on bioavailability have received attention only in recent years.