For many years there were no laws ruling the use of animals in scientific experimentation in Brazil. Standards set by national and international organizations were followed. Recently, Law No. 11.794/08 established procedures for the scientific use of animals. Studies in otolaryngology have used the larynxes of rabbits, pigs, dogs, guinea pigs (Cavia porcellus), and mice. There were also studies comparing rabbits, rats, and dogs, rhinoplasty on rabbits, and inner ear studies on rats and guinea pigs (albino).