**1. Introduction**

Infections caused by fungi, are the major problem of hospital infections, mainly due to the emergence of new infections and the generalized resistance to antibiotics [1]. Due to the rapid resistance acquired by microorganisms the search for natural products with antimicrobial activity has been constant in recent years and drugs derived from plants have contributed largely to human health, historically representing a source for the creation of new drugs [2].

One way of combating microbial resistance is the investigation of substances that can act as resistance modifiers by combining common antimicrobial drugs with some phytochemicals, and in some cases observed synergism [3,4].

Yeasts of the genus *Candida* are found as commensals in the human organism, however, because of factors that disturb the dynamics of the host can favor the growth of these fungi, from superficial infections to systemic infections [5]. Among the yeasts of this genus, *Candida albicans* stands out as the main cause of infections, being a species with grea<sup>t</sup> ability to change its morphology, a necessary factor for its virulence and pathogenicity [6,7].

For the treatment of infectious diseases, populations without access to medicines, especially those from underdeveloped and developing countries, use medicinal plants to combat disease. Such use of these vegetables is due to a number of advantages, such as their availability, low purchasing power and being in popular knowledge for several generations [2,8]. Among the species of the Brazilian flora, the genus *Piper* L. is one of the largest in the Piperaceae family, with 290 species and 45 varieties occurring in Brazil [9]. Some species of the genus are used as a flavoring of food and treatment of diseases [10]. A scientific study evidenced the antimicrobial potential of four species of the genus against *Staphylococcus aureus* and three strains of *Candida*, including *C. albicans* [11]. Among the species of the genus, *Piper caldense* C. DC., is popularly known in Brazil as "pimenta d'água" or "pimenta d'arda", being commonly used for the treatment of snake bites, sedative and stomach problems [10]. Research using *P. caldense* essential oil has revealed promising antimicrobial potential [12,13].

In view of the above problem, this study aimed to evaluate the antibiotic and modulator potential of volatile terpenes of *P. caldense* against *Candida albicans*, as well as to determine if the natural product is capable of reducing pleomorphism. Finally, it was evaluated by gas chromatography which terpenes were present in the essential oil.
