Introduction: Aluminum phosphide (AlP) is a common solid fumigant pesticide used for agricultural and nonagricultural purposes. In Egypt, AlP tablets are frequently used to commit suicide, and AlP poisoning constituting a frequent cause of admission and mortality in poison control centers. Current management of AlP poisoning is limited to supportive care; as there is no specific antidote. Objectives: to evaluate the therapeutic effect and safety of early L-carnitine administration, as an antioxidant, in treatment of severe acute AlP poisoning. Material and methods: This study was a randomized controlled clinical trial. It was conducted in Tanta Poison Control center (Emergency Hospital, Tanta University). Fifty acute AlP intoxicated patients were randomly allocated into two equal groups A and B using the sequentially numbered, opaque sealed envelopes method. Group A received only the routine treatment. Group B received L – Carnitine therapy as follow: 9 ampoules (9 gm) of L- Carnitine in 500 ml of 0.9% normal saline given as continuous IV infusion, until improvement or death in addition to the routine treatment. Complete physical examination, routine laboratory investigations and oxidative stress markers; malondialdehyde (MDA), total antioxidant capacity (TAC) and reduced glutathione (GSH) were assessed for each patient. Results: Comparison between groups A and B 12 hrs after admission revealed significant reduction of the mean MDA levels in group B than group A (7.54± 1.74 and 16.22± 2.95 respectively, p<0.001). At the same time, group B showed significant elevation in the mean TAC (5.70±1.55 and 12.88±2.49 respectively) and GSH levels (2.37±.89, 4.09±.86 respectively). Additionally, the need for intubation and mechanical ventilation was significantly lower in group B compared to group A (20% versus 56 % respectively). However, there was non-significant reduction in the number of deaths in patients on L-carnitine therapy (group B) compared with group A (60% and 80% respectively, p >0.05). Conclusion: Early administration of L-carnitine IV infusion was effective and safe as an adjuvant treatment of AlP poisoned patients.