Necrotising soft tissue infection is a rare and rapid process with devastating consequence. We report one case of necrotising soft tissue infection in a bilateral upper limb with uncommon oral bacteria. Radiological imaging revealed the presence of gas in upper limb soft tissues, and an MRI showed the localised signal changes in the biceps muscle of the right upper arm, and the subcutaneous tissue of the left elbow. The patient was treated with surgical resection of the infected muscle and wide debridement of the subcutaneous tissue. Antibiotics were initiated. The patient recovered immediately without functional deficit. The unique features of this patient were possible to observe in the progression of the necrotising soft tissue infection in the bilateral upper limb with intentional injection of oral bacteria, and the effect of biceps brachii resection in a prime age worker.