Candida albicans is a most common cause of fungal infections in animals and birds. Understanding the increasing resistance of C. albicans to various antifungal therapeutic agents is important to discover new anti-candidal alternatives. The present study investigated the anti-candidal potential of five endophytic fungi extracts, isolated from the tropical ethnoveterinary plant, Calotropis gigantea. We firstly evaluated the in vitro antifungal activities of endophytic fungi extracts by the well diffusion method. Secondly, the cells of C. albicans were treated with the potent extract to observe significant ultrastructural changes. To further investigate the in vivo antifungal activity of the extract, some laboratory experiments with mice were undertaken, and posteriourly, the different organs were studied under the electron microscope for any deformities. Phomopsis asparagi showed the best anti-candidal activity with a minimum inhibitory concentration (MIC) of 46.9 µg/mL. The fungal test pathogen (C. albicans) exhibited various cell deformities when treated with the extract of P. asparagi. Histopathological studies of the vital organs of mice treated with the potent fungal extract did not show any significant pathological conditions when viewed under scanning electron microscope. Thus, P. asparagi can be a potential candidate for anti-candidal agents against C. albicans. Future studies will focus on the isolation of the bioactive components of the extract. Rev. Biol. Trop. 65 (4): 1437-1447. Epub 2017 December 01.Key words: endophytic fungi, anti-candidal, Candida albicans, scanning electron microscope, ultrastructure.Candida albicans is recognized to cause many important diseases in animals and birds, and represents an important veterinary pathogen. C. albicans mostly affects birds causing thrush affecting the oral mucosa, oesophagus and crop. Cattle, calves, sheep and foals are also susceptible to systemic candidiasis which occurs as a consequence of prolonged treatment with antibiotics and corticosteroids (Kuwamura, Ide, Yamate, Shiraishi, & Kotani, 2006). C. albicans infections faces a number of problems including limited number of effective antifungal agents, toxicity of the available antifungal agents, resistance of Candida to commonly used antifungal, relapse of Candida infections and non-cost effective antifungal agents (Sasidharan, Zuraini, Latha, & Suryani, 2008). Therefore, there is an urgent need to design new drugs and to explore alternative sources of novel drugs.Northeast (NE) India is considered one of the most important biodiversity hotspots of the globe with a wide range of physiographic and ecoclimatic conditions (Myers, Mittermeier, Mittermeier, Fonseca, & Kent, 2000). Northeast India in the Eastern Himalayan range is located between 20°35'37.2624"N -78°57'46.368"E, and sprawling over 262 379 km 2 (Lyngwi, Koijam, Sharma, & Joshi, 2013). In tropical and subtropical countries, with hot and humid climates like India, with ideal conditions for fungal infections, turn them into a common p...