Clinical study was conducted on the used of black cumin oil (Nigella sativa L.) against persistent asthma patients at the pulmonary clinic of Dr M. Djamil Hospital, Padang. Asthmatic patients were divided into two groups: the control and treatment groups. The control group was given hospital standard therapy only, bronchodilator and controller, while the treatment group received standard therapy and black cumin oil with dose 60 mg/BW/day orally. The assessment was conducted on the level of asthma control, and the value of eosinophils blood during the first month of use. This study showed that black cumin oil increased the level of asthma control in patients as indicated by level up of ACT score ( p<0.05 ). The values of blood eosinophils decreased in the treatment group but not statistically significant when compared with the control group (p>0.05).