ObjectiveTo observe the effect of botanic antioxidant TA9901 o n injured motoneurons following brachial plexus root avulsion. MethodsBrachial p lexus root avulsion model was made in 90 adult Sprague-Dawley female rats. Then the animals were divided into 2 groups, with 45 each. The experiment group recei ved 1ml intraperitoneal injection of 0.5% TA9901 (TA9901 group) while the contro l group received normal saline everyday. The rats were killed after antioxidant treatment for 4 hours to 6 weeks. The C7 segments were examined with c-jun immu n ohistochemistry and neutral red stain. The numbers of c-jun positive and surviv a l motoneurons in the lesion side were counted and compared between the two group s. ResultsThe number of c-jun positive motoneurons was signif icantly increased in TA9901 group than that in control group at 3 days, 5 days, 1 week, and 2 w eeks respectively. The number of surviving motoneurons was also significantly in creased in TA9901 group than that in control group at 2 weeks, 4 weeks, and 6 w eeks respectively. ConclusionTA9901 can up-regulate c-jun ex pression and enha nce the survival of spinal motoneurons following brachial plexus root avulsion.