The farming of small ruminants in semiarid regions faces significant challenges due to harsh climatic conditions that induce high levels of heat stress. This study evaluated the effects of wood vinegar (pyroligneous extract) on the thermoregulation of confined sheep in a semiarid environment, addressing the problem of heat stress that compromises animal welfare and productivity. The objective was to evaluate whether increasing oral doses of wood vinegar improve thermoregulatory responses in confined sheep under high heat load. The experiment was conducted in the semiarid region of Northeastern Brazil with five crossbred sheep (1/2 Dorper x 1/2 Santa In & ecirc;s) in a 5 x 5 Latin square design. Treatments consisted of increasing oral doses of wood vinegar (0, 10, 20, 30, and 40 mL/day). Environmental and physiological variables were monitored over five periods of 17 days each. Data were analyzed using ANOVA followed by Tukey's test. The results indicated that the 40 mL/day dose significantly reduced rectal temperature (Tr, degrees C) and respiratory rate (Rr) compared to the control group, demonstrating greater thermoregulatory efficiency and highlighting the potential of wood vinegar to mitigate the physiological impacts of heat. This study contributes to sustainable nutritional strategies for livestock production in semiarid climates, emphasizing wood vinegar as a promising feed additive. Future research should further investigate the mechanisms and long-term effects of this supplementation.