The activity of essential oil from Achyrocline alta is probably due to the high concentration of terpenoids (22), which have been evaluated for their in vitro antimycobacterial activity (8,23). More specifically, thymol has an antimycobacterial activity with a MIC of 100 μg mL-1 (24). Other terpenes as carvacrol and α-pinene have shown a MIC against M. tuberculosis H37Rv of 64 and 128 μg mL1 respectively (25). In addition, the antitubercular activity of citronellol, nerol and