In the present study, we aimed to assess the toxicity of artemisinin on the haematological system and its effect on the productive performance of broiler chickens. Eighteen-day-old chickens were randomly divided into four groups of 30 chickens (three replicates of 10 broilers/group): control group and three experimental groups: ART5 - diet with 5 ppm of artemisinin; ART50 - diet with 50 ppm of artemisinin; and ART500 - diet with 500 ppm of artemisinin. Artemisinin enhanced the productive performances of broiler chickens at the lowest concentration (5 ppm), but at the highest concentration (500 ppm), it negatively affected weight gain and the feed conversion ratio. The performance characteristics of the chickens whose diets were supplemented with 50 ppm artemisinin were similar to those of the control group. Additionally, 5 ppm artemisinin in feed did not significantly affect the haematological parameters of the chickens, but 50 and 500 ppm artemisinin induced a gradual decline of the total leukocytes, lymphopenia, monocytosis, and eosinopenia, and the highest concentration caused anaemia. Artemisinin at a low concentration could be used as a feed additive in the poultry industry to improve organic broiler production performance with no serious side effects.