A phytochemical screening of Erythrina mysorensis was carried out and its nutritive potential was determined by in vitro gas production. The samples were selected according to completely randomized design in the experimental area. The chemical composition (DM, OM, ash, CP, ADF, NDF, hemicellulose and cellular content) was determined, as well as the presence of secondary metabolites. Incubation times for gas production of 0, 3, 6, 9, 127, 15, 18, 21, 24, 48, 72, 96, 120 and 144 h were used. Alkaloids, amino acids, tannins and/or phenolic compounds and triterpens and/or steroids were identified. The compounds with higher content in the plant were the resins. An average value of 0.55 mL/h was attained in gas production. The results of the plant foliage fermentation were adjusted according to the Logistical and Monomolecular models with R-2 of 0.97 and 0.99, respectively. The results showed that the foliage of Erythrina mysorensis has an adequate nutritive potential for ruminant feeding. Besides, new researches are suggested in which the effect of the resins and the alkaloids on voluntary intake and the ruminal environment of the animals fed with this plant is further studied. The Logistical and Monomolecular models can be used for this type of analysis and included in the group formed by the most used mathematical models to adjust in vitro gas production as microbial fermentation index. The use of larger number of samples is suggested for further studies.