Simpson fell ill with diarrhoea during the Tour's tenth stage. He was under pressure from his personal manager to continue in the race, though members of his team encouraged him to quit. Near the summit of Mont Ventoux, Simpson fell off of his bike but was able to get back on it. After riding a short distance further, he collapsed. He was pronounced dead after being airlifted to a hospital. The post-mortem examination found that Simpson had taken amphetamine and alcohol, a diuretic combination which proved fatal when combined with the heat, the hard climb of the Ventoux and the stomach complaint.