>The physicians found she had taken a relatively long car journey, of about an hour and a half, the day before; took a daily dose of oestrogen oral contraceptives; and had a genetic variant, called the factor V Leiden mutation, which is linked to a blood-clot disorder. >All are well-established factors for causing deep vein thrombosis (DVT), as these dangerous events are called. >But what "may well have tipped the balance" is that she had been eating a grapefruit every morning under a weight-loss diet begun three days earlier, the report said. >Grapefruit juice is known to block the action of an enzyme called CYP3A4 which breaks down the contraceptive hormone oestrogen. >However, it's important to keep a sense of perspective. Commenting on the findings at the time, Doctor Trevor Baglin, Consultant Haematologist, Addenbrooke’s NHS Trust, said: “From this case study it appears as if the grapefruit enhanced the thrombotic effect of the contraceptive pill in the presence of a genetic predisposition." Okay. So nothing to see here, at all. Just an odd set of events.