Four beef Holstein heifers (BW = 438 ± 71 kg) fitted with a 1-cm i.d. plastic ruminal trocars were used in a 4 × 4 Latin square design to evaluate the effect of 3 doses of capsicum extract (CAP) on intake, water consumption, and ruminal fermentation in heifers fed a high-concentrate diet. Animals were fed (DM basis) 10% barley straw and 90% concentrate (32.2% barley grain, 27.9% ground corn, 7.5% wheat bran, 10.7% soybean meal, 10.7% soybean hulls, 7.2% corn gluten feed, 3.1% mineral-vitamin mix; 16.6% CP, 18.3% NDF). Treatments were no additive (CTR), 125 (CAP125), 250 (CAP250), and 500 (CAP500) mg/d of capsicum oleoresin standardized with 6% of capsaicin and dihydrocapsaicin (XTract 6933, Pancosma, Geneva, Switzerland). Each experimental period consisted of 25 d (15 d for adaptation, 5 d of continuous measurement of DMI, and 3 d for rumen sample collection). Animals had ad libitum access to water and feed offered once daily at 0800 h. Data were analyzed by the MIXED procedure of SAS. The model included the fixed effects of period and treatment, the random effect of heifer, and the residual error. The effects were tested for linear and quadratic effects. A linear response was observed (CTR, CAP125, CAP250, and CAP500, respectively) for DMI (8.56, 9.84, 8.68, and 9.40 kg/d; P < 0.04), ruminal pH (6.03, 5.84, 5.96, and 5.86; P < 0.08) and total VFA (134.3, 144.8, 140.1, and 142.8 mM; P < 0.08). There was a strong correlation between water consumption and DMI (R(2) = 0.98). Dry matter intake in the first 2 h after feeding was reduced (P < 0.05) in all CAP treatments compared with control. The molar proportion of acetate tended to decrease linearly (from 59.6 to 55.5 mol/100 mol; P < 0.06), and ammonia N concentration tended to increase linearly (from 14.4 to 16.0 mg N/dL; P < 0.08). In contrast, the molar proportion of propionate (23.8 mol/100 mol), butyrate (14.2 mol/100 mol), and lactate (0.28 mol/100 mol) were not affected by treatments. Results indicate that capsicum extract stimulated DMI and modified the pattern of DMI in beef cattle fed high concentrate diets.