Diet is one of many factors that could alter the pharmacokinetics of drugs. Several fruits and berries have recently been shown to contain agents that affect drug-metabolizing enzymes. Grapefruit is the most well-known example, but also Sevillian orange, pomelo and star fruit contain agents that inhibit cytochrome P450 3A4 (CYP3A4), which is the most important enzyme in drug metabolism. The present article reviews published information on potential interactions between drugs and fruits/berries, with main focus on inhibition and induction of metabolizing enzymes.