The influence of pepper (Capsicum ssp.) as a feed additive to balanced sheep rations on the in vitro digestibility coefficient of nutrients and their fermentation parameters was evaluated in two different inocula: rumen liquid and sheep feces. Four inclusion levels of pepper (0.0%, 0.2%, 0.4% and 0.6% of DM) and two types of inoculum were arranged in a 4 x 2 factorial arrangement, in a completely randomized design. Experimental rations were balanced to include 0.0%; 0.2%; 0.4% and 0.6% Capsicum ssp., with 13.5% crude protein and 70.0% total digestible nutrients (TDN). A basal diet of 60% bulk (corn silage) and 40% of the concentrate containing 0.0% Capsicum ssp. was given to the inoculant donor animals. Two sheep with a mean bodyweight of 27.6 + 1.6 kg were used as inoculum donors (ruminal fluid and feces) for the determination of the IVDC of nutrients. The variables studied were submitted for analysis of variance and the inclusion levels of pepper. Regression analysis was performed at 5% of probability and for the different inocula, a Tukey test was performed at 5% significance. The different levels of inclusion of pepper (0.0%, 0.2%, 0.4%, and 0.6%) in the balanced sheep rations were not altered (P > 0.05) the IVDC of DM; OM; CP and NDF for both inocula (ruminal fluid and sheep feces). However, the use of the different inocula resulted in a change (P < 0.05) in the IVDC value of DM, OM, CP, and NDF, in which the ruminal liquid inoculum presented higher (P < 0.05) values of IVDC for the ration nutrients in relation to sheep feces. The levels of 0, 0%; 0.2%; 0.4% and 0.6% of pepper in ruminant feeds did not change the pH value of the fermented content after a 24-hour in vitro incubation (P > 0.05). However, the use of ruminal liquid as inoculum for the in vitro fermentation of the experimental rations provided a lower value (P < 0.05) for the pH of the fermented content in relation to the sheep feces. The inclusion of this phytogenic additive in ruminant feeds and the use of inoculum based on rumen fluid or sheep feces did not cause changes in the concentration of ammoniacal nitrogen (N-NH3) in the fermented rations after incubation (P > 0.05) for 24 hours in vitro. Thus, the inclusion of up to 0.6% Capsicum ssp. (pepper) in balanced rations for ruminants does not alter the in vitro digestibility coefficient of dry matter, organic matter, crude protein, and neutral detergent fiber, or the in vitro fermentation parameters. However, the use of ruminal fluid as inoculum for the in vitro fermentation presented values of a higher degree of confidence in relation to feces to determine the in vitro digestion coefficient of the nutrients.