Farmacias Similares can seem an unserious business. Employees dressed as the company’s mascot, the moustachioed “Dr Simi”, dance outside its pharmacies. Stuffed-toy Simis, costumed as Jedi knights or musicians in traditional mariachi style, adorn its headquarters in Mexico City. But behind the cutesy marketing is a firm that has made health care in Mexico dramatically cheaper and more accessible over the past three decades. It is now trying to push into the United States.